xref: /linux/arch/x86/kernel/apm_32.c (revision 791d3ef2e11100449837dc0b6fe884e60ca3a484)
1 /* -*- linux-c -*-
2  * APM BIOS driver for Linux
3  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
4  *
5  * Initial development of this driver was funded by NEC Australia P/L
6  *	and NEC Corporation
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the
10  * Free Software Foundation; either version 2, or (at your option) any
11  * later version.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * October 1995, Rik Faith (faith@cs.unc.edu):
19  *    Minor enhancements and updates (to the patch set) for 1.3.x
20  *    Documentation
21  * January 1996, Rik Faith (faith@cs.unc.edu):
22  *    Make /proc/apm easy to format (bump driver version)
23  * March 1996, Rik Faith (faith@cs.unc.edu):
24  *    Prohibit APM BIOS calls unless apm_enabled.
25  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
26  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
27  *    Version 1.0 and 1.1
28  * May 1996, Version 1.2
29  * Feb 1998, Version 1.3
30  * Feb 1998, Version 1.4
31  * Aug 1998, Version 1.5
32  * Sep 1998, Version 1.6
33  * Nov 1998, Version 1.7
34  * Jan 1999, Version 1.8
35  * Jan 1999, Version 1.9
36  * Oct 1999, Version 1.10
37  * Nov 1999, Version 1.11
38  * Jan 2000, Version 1.12
39  * Feb 2000, Version 1.13
40  * Nov 2000, Version 1.14
41  * Oct 2001, Version 1.15
42  * Jan 2002, Version 1.16
43  * Oct 2002, Version 1.16ac
44  *
45  * History:
46  *    0.6b: first version in official kernel, Linux 1.3.46
47  *    0.7: changed /proc/apm format, Linux 1.3.58
48  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
49  *    0.9: only call bios if bios is present, Linux 1.3.72
50  *    1.0: use fixed device number, consolidate /proc/apm into this file,
51  *         Linux 1.3.85
52  *    1.1: support user-space standby and suspend, power off after system
53  *         halted, Linux 1.3.98
54  *    1.2: When resetting RTC after resume, take care so that the time
55  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
56  *         <jtoth@princeton.edu>); improve interaction between
57  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
58  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
59  *	   levels to the printk calls. APM is not defined for SMP machines.
60  *         The new replacement for it is, but Linux doesn't yet support this.
61  *         Alan Cox Linux 2.1.55
62  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
63  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
64  *         Dean Gaudet <dgaudet@arctic.org>.
65  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
66  *    1.5: Fix segment register reloading (in case of bad segments saved
67  *         across BIOS call).
68  *         Stephen Rothwell
69  *    1.6: Cope with compiler/assembler differences.
70  *         Only try to turn off the first display device.
71  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
72  *                   <echter@informatik.uni-rostock.de>
73  *         Stephen Rothwell
74  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
75  *         to reflect current state of APM BIOS.
76  *         Chris Rankin <rankinc@bellsouth.net>
77  *         Reset interrupt 0 timer to 100Hz after suspend
78  *         Chad Miller <cmiller@surfsouth.com>
79  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
80  *         Richard Gooch <rgooch@atnf.csiro.au>
81  *         Allow boot time disabling of APM
82  *         Make boot messages far less verbose by default
83  *         Make asm safer
84  *         Stephen Rothwell
85  *    1.8: Add CONFIG_APM_RTC_IS_GMT
86  *         Richard Gooch <rgooch@atnf.csiro.au>
87  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
88  *         remove dependency on CONFIG_PROC_FS
89  *         Stephen Rothwell
90  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
91  *         Try to cope with BIOS's that need to have all display
92  *         devices blanked and not just the first one.
93  *         Ross Paterson <ross@soi.city.ac.uk>
94  *         Fix segment limit setting it has always been wrong as
95  *         the segments needed to have byte granularity.
96  *         Mark a few things __init.
97  *         Add hack to allow power off of SMP systems by popular request.
98  *         Use CONFIG_SMP instead of __SMP__
99  *         Ignore BOUNCES for three seconds.
100  *         Stephen Rothwell
101  *   1.10: Fix for Thinkpad return code.
102  *         Merge 2.2 and 2.3 drivers.
103  *         Remove APM dependencies in arch/i386/kernel/process.c
104  *         Remove APM dependencies in drivers/char/sysrq.c
105  *         Reset time across standby.
106  *         Allow more inititialisation on SMP.
107  *         Remove CONFIG_APM_POWER_OFF and make it boot time
108  *         configurable (default on).
109  *         Make debug only a boot time parameter (remove APM_DEBUG).
110  *         Try to blank all devices on any error.
111  *   1.11: Remove APM dependencies in drivers/char/console.c
112  *         Check nr_running to detect if we are idle (from
113  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
114  *         Fix for bioses that don't zero the top part of the
115  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
116  *         (reported by Panos Katsaloulis <teras@writeme.com>).
117  *         Real mode power off patch (Walter Hofmann
118  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
119  *   1.12: Remove CONFIG_SMP as the compiler will optimize
120  *         the code away anyway (smp_num_cpus == 1 in UP)
121  *         noted by Artur Skawina <skawina@geocities.com>.
122  *         Make power off under SMP work again.
123  *         Fix thinko with initial engaging of BIOS.
124  *         Make sure power off only happens on CPU 0
125  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
126  *         Do error notification to user mode if BIOS calls fail.
127  *         Move entrypoint offset fix to ...boot/setup.S
128  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
129  *         Remove smp-power-off. SMP users must now specify
130  *         "apm=power-off" on the kernel command line. Suggested
131  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
132  *         <alan@lxorguk.ukuu.org.uk>.
133  *         Register the /proc/apm entry even on SMP so that
134  *         scripts that check for it before doing power off
135  *         work (Jim Avera <jima@hal.com>).
136  *   1.13: Changes for new pm_ interfaces (Andy Henroid
137  *         <andy_henroid@yahoo.com>).
138  *         Modularize the code.
139  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
140  *         is now the way life works).
141  *         Fix thinko in suspend() (wrong return).
142  *         Notify drivers on critical suspend.
143  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
144  *         modified by sfr).
145  *         Disable interrupts while we are suspended (Andy Henroid
146  *         <andy_henroid@yahoo.com> fixed by sfr).
147  *         Make power off work on SMP again (Tony Hoyle
148  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
149  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
150  *         interval is now configurable.
151  *   1.14: Make connection version persist across module unload/load.
152  *         Enable and engage power management earlier.
153  *         Disengage power management on module unload.
154  *         Changed to use the sysrq-register hack for registering the
155  *         power off function called by magic sysrq based upon discussions
156  *         in irc://irc.openprojects.net/#kernelnewbies
157  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
158  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
159  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
160  *         Work around byte swap bug in one of the Vaio's BIOS's
161  *         (Marc Boucher <marc@mbsi.ca>).
162  *         Exposed the disable flag to dmi so that we can handle known
163  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
164  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
165  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
166  *         If an APM idle fails log it and idle sensibly
167  *   1.15: Don't queue events to clients who open the device O_WRONLY.
168  *         Don't expect replies from clients who open the device O_RDONLY.
169  *         (Idea from Thomas Hood)
170  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
171  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
172  *         Notify listeners of standby or suspend events before notifying
173  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
174  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
175  *         Ignore first resume after we generate our own resume event
176  *         after a suspend (Thomas Hood)
177  *         Daemonize now gets rid of our controlling terminal (sfr).
178  *         CONFIG_APM_CPU_IDLE now just affects the default value of
179  *         idle_threshold (sfr).
180  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
181  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
182  *	   make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
183  *	   TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
184  *
185  * APM 1.1 Reference:
186  *
187  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
188  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
189  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
190  *
191  * [This document is available free from Intel by calling 800.628.8686 (fax
192  * 916.356.6100) or 800.548.4725; or from
193  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
194  * available from Microsoft by calling 206.882.8080.]
195  *
196  * APM 1.2 Reference:
197  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
198  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
199  *
200  * [This document is available from Microsoft at:
201  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
202  */
203 
204 #define pr_fmt(fmt) "apm: " fmt
205 
206 #include <linux/module.h>
207 
208 #include <linux/poll.h>
209 #include <linux/types.h>
210 #include <linux/stddef.h>
211 #include <linux/timer.h>
212 #include <linux/fcntl.h>
213 #include <linux/slab.h>
214 #include <linux/stat.h>
215 #include <linux/proc_fs.h>
216 #include <linux/seq_file.h>
217 #include <linux/miscdevice.h>
218 #include <linux/apm_bios.h>
219 #include <linux/init.h>
220 #include <linux/time.h>
221 #include <linux/sched/signal.h>
222 #include <linux/sched/cputime.h>
223 #include <linux/pm.h>
224 #include <linux/capability.h>
225 #include <linux/device.h>
226 #include <linux/kernel.h>
227 #include <linux/freezer.h>
228 #include <linux/smp.h>
229 #include <linux/dmi.h>
230 #include <linux/suspend.h>
231 #include <linux/kthread.h>
232 #include <linux/jiffies.h>
233 #include <linux/acpi.h>
234 #include <linux/syscore_ops.h>
235 #include <linux/i8253.h>
236 #include <linux/cpuidle.h>
237 
238 #include <linux/uaccess.h>
239 #include <asm/desc.h>
240 #include <asm/olpc.h>
241 #include <asm/paravirt.h>
242 #include <asm/reboot.h>
243 
244 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
245 extern int (*console_blank_hook)(int);
246 #endif
247 
248 /*
249  * The apm_bios device is one of the misc char devices.
250  * This is its minor number.
251  */
252 #define	APM_MINOR_DEV	134
253 
254 /*
255  * Various options can be changed at boot time as follows:
256  * (We allow underscores for compatibility with the modules code)
257  *	apm=on/off			enable/disable APM
258  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
259  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
260  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
261  *	    					powering off
262  *	    [no-]debug			log some debugging messages
263  *	    [no-]power[-_]off		power off on shutdown
264  *	    [no-]smp			Use apm even on an SMP box
265  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
266  *	    				bounces
267  *          idle[-_]threshold=<n>       System idle percentage above which to
268  *                                      make APM BIOS idle calls. Set it to
269  *                                      100 to disable.
270  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
271  *                                      which the idle percentage is
272  *                                      calculated.
273  */
274 
275 /* KNOWN PROBLEM MACHINES:
276  *
277  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
278  *                         [Confirmed by TI representative]
279  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
280  *                    [Confirmed by BIOS disassembly]
281  *                    [This may work now ...]
282  * P: Toshiba 1950S: battery life information only gets updated after resume
283  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
284  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
285  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
286  * 	Neale Banks <neale@lowendale.com.au> December 2000
287  *
288  * Legend: U = unusable with APM patches
289  *         P = partially usable with APM patches
290  */
291 
292 /*
293  * Define as 1 to make the driver always call the APM BIOS busy
294  * routine even if the clock was not reported as slowed by the
295  * idle routine.  Otherwise, define as 0.
296  */
297 #define ALWAYS_CALL_BUSY   1
298 
299 /*
300  * Define to make the APM BIOS calls zero all data segment registers (so
301  * that an incorrect BIOS implementation will cause a kernel panic if it
302  * tries to write to arbitrary memory).
303  */
304 #define APM_ZERO_SEGS
305 
306 #include <asm/apm.h>
307 
308 /*
309  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
310  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
311  * David Chen <chen@ctpa04.mit.edu>
312  */
313 #undef INIT_TIMER_AFTER_SUSPEND
314 
315 #ifdef INIT_TIMER_AFTER_SUSPEND
316 #include <linux/timex.h>
317 #include <asm/io.h>
318 #include <linux/delay.h>
319 #endif
320 
321 /*
322  * Need to poll the APM BIOS every second
323  */
324 #define APM_CHECK_TIMEOUT	(HZ)
325 
326 /*
327  * Ignore suspend events for this amount of time after a resume
328  */
329 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
330 
331 /*
332  * Maximum number of events stored
333  */
334 #define APM_MAX_EVENTS		20
335 
336 /*
337  * The per-file APM data
338  */
339 struct apm_user {
340 	int		magic;
341 	struct apm_user *next;
342 	unsigned int	suser: 1;
343 	unsigned int	writer: 1;
344 	unsigned int	reader: 1;
345 	unsigned int	suspend_wait: 1;
346 	int		suspend_result;
347 	int		suspends_pending;
348 	int		standbys_pending;
349 	int		suspends_read;
350 	int		standbys_read;
351 	int		event_head;
352 	int		event_tail;
353 	apm_event_t	events[APM_MAX_EVENTS];
354 };
355 
356 /*
357  * The magic number in apm_user
358  */
359 #define APM_BIOS_MAGIC		0x4101
360 
361 /*
362  * idle percentage above which bios idle calls are done
363  */
364 #ifdef CONFIG_APM_CPU_IDLE
365 #define DEFAULT_IDLE_THRESHOLD	95
366 #else
367 #define DEFAULT_IDLE_THRESHOLD	100
368 #endif
369 #define DEFAULT_IDLE_PERIOD	(100 / 3)
370 
371 static int apm_cpu_idle(struct cpuidle_device *dev,
372 			struct cpuidle_driver *drv, int index);
373 
374 static struct cpuidle_driver apm_idle_driver = {
375 	.name = "apm_idle",
376 	.owner = THIS_MODULE,
377 	.states = {
378 		{ /* entry 0 is for polling */ },
379 		{ /* entry 1 is for APM idle */
380 			.name = "APM",
381 			.desc = "APM idle",
382 			.exit_latency = 250,	/* WAG */
383 			.target_residency = 500,	/* WAG */
384 			.enter = &apm_cpu_idle
385 		},
386 	},
387 	.state_count = 2,
388 };
389 
390 static struct cpuidle_device apm_cpuidle_device;
391 
392 /*
393  * Local variables
394  */
395 __visible struct {
396 	unsigned long	offset;
397 	unsigned short	segment;
398 } apm_bios_entry;
399 static int clock_slowed;
400 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
401 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
402 static int suspends_pending;
403 static int standbys_pending;
404 static int ignore_sys_suspend;
405 static int ignore_normal_resume;
406 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
407 
408 static bool debug __read_mostly;
409 static bool smp __read_mostly;
410 static int apm_disabled = -1;
411 #ifdef CONFIG_SMP
412 static bool power_off;
413 #else
414 static bool power_off = 1;
415 #endif
416 static bool realmode_power_off;
417 #ifdef CONFIG_APM_ALLOW_INTS
418 static bool allow_ints = 1;
419 #else
420 static bool allow_ints;
421 #endif
422 static bool broken_psr;
423 
424 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
425 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
426 static struct apm_user *user_list;
427 static DEFINE_SPINLOCK(user_list_lock);
428 static DEFINE_MUTEX(apm_mutex);
429 
430 /*
431  * Set up a segment that references the real mode segment 0x40
432  * that extends up to the end of page zero (that we have reserved).
433  * This is for buggy BIOS's that refer to (real mode) segment 0x40
434  * even though they are called in protected mode.
435  */
436 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
437 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
438 
439 static const char driver_version[] = "1.16ac";	/* no spaces */
440 
441 static struct task_struct *kapmd_task;
442 
443 /*
444  *	APM event names taken from the APM 1.2 specification. These are
445  *	the message codes that the BIOS uses to tell us about events
446  */
447 static const char * const apm_event_name[] = {
448 	"system standby",
449 	"system suspend",
450 	"normal resume",
451 	"critical resume",
452 	"low battery",
453 	"power status change",
454 	"update time",
455 	"critical suspend",
456 	"user standby",
457 	"user suspend",
458 	"system standby resume",
459 	"capabilities change"
460 };
461 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
462 
463 typedef struct lookup_t {
464 	int	key;
465 	char 	*msg;
466 } lookup_t;
467 
468 /*
469  *	The BIOS returns a set of standard error codes in AX when the
470  *	carry flag is set.
471  */
472 
473 static const lookup_t error_table[] = {
474 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
475 	{ APM_DISABLED,		"Power management disabled" },
476 	{ APM_CONNECTED,	"Real mode interface already connected" },
477 	{ APM_NOT_CONNECTED,	"Interface not connected" },
478 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
479 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
480 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
481 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
482 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
483 	{ APM_BAD_PARAM,	"Parameter out of range" },
484 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
485 	{ APM_BAD_FUNCTION,     "Function not supported" },
486 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
487 	{ APM_BAD_STATE,	"Unable to enter requested state" },
488 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
489 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
490 	{ APM_NOT_PRESENT,	"No APM present" }
491 };
492 #define ERROR_COUNT	ARRAY_SIZE(error_table)
493 
494 /**
495  *	apm_error	-	display an APM error
496  *	@str: information string
497  *	@err: APM BIOS return code
498  *
499  *	Write a meaningful log entry to the kernel log in the event of
500  *	an APM error.  Note that this also handles (negative) kernel errors.
501  */
502 
503 static void apm_error(char *str, int err)
504 {
505 	int i;
506 
507 	for (i = 0; i < ERROR_COUNT; i++)
508 		if (error_table[i].key == err)
509 			break;
510 	if (i < ERROR_COUNT)
511 		pr_notice("%s: %s\n", str, error_table[i].msg);
512 	else if (err < 0)
513 		pr_notice("%s: linux error code %i\n", str, err);
514 	else
515 		pr_notice("%s: unknown error code %#2.2x\n",
516 		       str, err);
517 }
518 
519 /*
520  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
521  * apm_info.allow_ints, we are being really paranoid here!  Not only
522  * are interrupts disabled, but all the segment registers (except SS)
523  * are saved and zeroed this means that if the BIOS tries to reference
524  * any data without explicitly loading the segment registers, the kernel
525  * will fault immediately rather than have some unforeseen circumstances
526  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
527  * this depends on CS referring to the same physical memory as DS so that
528  * DS can be zeroed before the call. Unfortunately, we can't do anything
529  * about the stack segment/pointer.  Also, we tell the compiler that
530  * everything could change.
531  *
532  * Also, we KNOW that for the non error case of apm_bios_call, there
533  * is no useful data returned in the low order 8 bits of eax.
534  */
535 
536 static inline unsigned long __apm_irq_save(void)
537 {
538 	unsigned long flags;
539 	local_save_flags(flags);
540 	if (apm_info.allow_ints) {
541 		if (irqs_disabled_flags(flags))
542 			local_irq_enable();
543 	} else
544 		local_irq_disable();
545 
546 	return flags;
547 }
548 
549 #define apm_irq_save(flags) \
550 	do { flags = __apm_irq_save(); } while (0)
551 
552 static inline void apm_irq_restore(unsigned long flags)
553 {
554 	if (irqs_disabled_flags(flags))
555 		local_irq_disable();
556 	else if (irqs_disabled())
557 		local_irq_enable();
558 }
559 
560 #ifdef APM_ZERO_SEGS
561 #	define APM_DECL_SEGS \
562 		unsigned int saved_fs; unsigned int saved_gs;
563 #	define APM_DO_SAVE_SEGS \
564 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
565 #	define APM_DO_RESTORE_SEGS \
566 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
567 #else
568 #	define APM_DECL_SEGS
569 #	define APM_DO_SAVE_SEGS
570 #	define APM_DO_RESTORE_SEGS
571 #endif
572 
573 struct apm_bios_call {
574 	u32 func;
575 	/* In and out */
576 	u32 ebx;
577 	u32 ecx;
578 	/* Out only */
579 	u32 eax;
580 	u32 edx;
581 	u32 esi;
582 
583 	/* Error: -ENOMEM, or bits 8-15 of eax */
584 	int err;
585 };
586 
587 /**
588  *	__apm_bios_call - Make an APM BIOS 32bit call
589  *	@_call: pointer to struct apm_bios_call.
590  *
591  *	Make an APM call using the 32bit protected mode interface. The
592  *	caller is responsible for knowing if APM BIOS is configured and
593  *	enabled. This call can disable interrupts for a long period of
594  *	time on some laptops.  The return value is in AH and the carry
595  *	flag is loaded into AL.  If there is an error, then the error
596  *	code is returned in AH (bits 8-15 of eax) and this function
597  *	returns non-zero.
598  *
599  *	Note: this makes the call on the current CPU.
600  */
601 static long __apm_bios_call(void *_call)
602 {
603 	APM_DECL_SEGS
604 	unsigned long		flags;
605 	int			cpu;
606 	struct desc_struct	save_desc_40;
607 	struct desc_struct	*gdt;
608 	struct apm_bios_call	*call = _call;
609 
610 	cpu = get_cpu();
611 	BUG_ON(cpu != 0);
612 	gdt = get_cpu_gdt_rw(cpu);
613 	save_desc_40 = gdt[0x40 / 8];
614 	gdt[0x40 / 8] = bad_bios_desc;
615 
616 	apm_irq_save(flags);
617 	APM_DO_SAVE_SEGS;
618 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
619 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
620 			  &call->esi);
621 	APM_DO_RESTORE_SEGS;
622 	apm_irq_restore(flags);
623 	gdt[0x40 / 8] = save_desc_40;
624 	put_cpu();
625 
626 	return call->eax & 0xff;
627 }
628 
629 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
630 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
631 {
632 	int ret;
633 
634 	/* Don't bother with work_on_cpu in the common case, so we don't
635 	 * have to worry about OOM or overhead. */
636 	if (get_cpu() == 0) {
637 		ret = fn(call);
638 		put_cpu();
639 	} else {
640 		put_cpu();
641 		ret = work_on_cpu(0, fn, call);
642 	}
643 
644 	/* work_on_cpu can fail with -ENOMEM */
645 	if (ret < 0)
646 		call->err = ret;
647 	else
648 		call->err = (call->eax >> 8) & 0xff;
649 
650 	return ret;
651 }
652 
653 /**
654  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
655  *	@call: the apm_bios_call registers.
656  *
657  *	If there is an error, it is returned in @call.err.
658  */
659 static int apm_bios_call(struct apm_bios_call *call)
660 {
661 	return on_cpu0(__apm_bios_call, call);
662 }
663 
664 /**
665  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
666  *	@_call: pointer to struct apm_bios_call.
667  *
668  *	Make a BIOS call that returns one value only, or just status.
669  *	If there is an error, then the error code is returned in AH
670  *	(bits 8-15 of eax) and this function returns non-zero (it can
671  *	also return -ENOMEM). This is used for simpler BIOS operations.
672  *	This call may hold interrupts off for a long time on some laptops.
673  *
674  *	Note: this makes the call on the current CPU.
675  */
676 static long __apm_bios_call_simple(void *_call)
677 {
678 	u8			error;
679 	APM_DECL_SEGS
680 	unsigned long		flags;
681 	int			cpu;
682 	struct desc_struct	save_desc_40;
683 	struct desc_struct	*gdt;
684 	struct apm_bios_call	*call = _call;
685 
686 	cpu = get_cpu();
687 	BUG_ON(cpu != 0);
688 	gdt = get_cpu_gdt_rw(cpu);
689 	save_desc_40 = gdt[0x40 / 8];
690 	gdt[0x40 / 8] = bad_bios_desc;
691 
692 	apm_irq_save(flags);
693 	APM_DO_SAVE_SEGS;
694 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
695 					 &call->eax);
696 	APM_DO_RESTORE_SEGS;
697 	apm_irq_restore(flags);
698 	gdt[0x40 / 8] = save_desc_40;
699 	put_cpu();
700 	return error;
701 }
702 
703 /**
704  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
705  *	@func: APM function to invoke
706  *	@ebx_in: EBX register value for BIOS call
707  *	@ecx_in: ECX register value for BIOS call
708  *	@eax: EAX register on return from the BIOS call
709  *	@err: bits
710  *
711  *	Make a BIOS call that returns one value only, or just status.
712  *	If there is an error, then the error code is returned in @err
713  *	and this function returns non-zero. This is used for simpler
714  *	BIOS operations.  This call may hold interrupts off for a long
715  *	time on some laptops.
716  */
717 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
718 				int *err)
719 {
720 	struct apm_bios_call call;
721 	int ret;
722 
723 	call.func = func;
724 	call.ebx = ebx_in;
725 	call.ecx = ecx_in;
726 
727 	ret = on_cpu0(__apm_bios_call_simple, &call);
728 	*eax = call.eax;
729 	*err = call.err;
730 	return ret;
731 }
732 
733 /**
734  *	apm_driver_version	-	APM driver version
735  *	@val:	loaded with the APM version on return
736  *
737  *	Retrieve the APM version supported by the BIOS. This is only
738  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
739  *	probably present.
740  *
741  *	On entry val should point to a value indicating the APM driver
742  *	version with the high byte being the major and the low byte the
743  *	minor number both in BCD
744  *
745  *	On return it will hold the BIOS revision supported in the
746  *	same format.
747  */
748 
749 static int apm_driver_version(u_short *val)
750 {
751 	u32 eax;
752 	int err;
753 
754 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
755 		return err;
756 	*val = eax;
757 	return APM_SUCCESS;
758 }
759 
760 /**
761  *	apm_get_event	-	get an APM event from the BIOS
762  *	@event: pointer to the event
763  *	@info: point to the event information
764  *
765  *	The APM BIOS provides a polled information for event
766  *	reporting. The BIOS expects to be polled at least every second
767  *	when events are pending. When a message is found the caller should
768  *	poll until no more messages are present.  However, this causes
769  *	problems on some laptops where a suspend event notification is
770  *	not cleared until it is acknowledged.
771  *
772  *	Additional information is returned in the info pointer, providing
773  *	that APM 1.2 is in use. If no messges are pending the value 0x80
774  *	is returned (No power management events pending).
775  */
776 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
777 {
778 	struct apm_bios_call call;
779 
780 	call.func = APM_FUNC_GET_EVENT;
781 	call.ebx = call.ecx = 0;
782 
783 	if (apm_bios_call(&call))
784 		return call.err;
785 
786 	*event = call.ebx;
787 	if (apm_info.connection_version < 0x0102)
788 		*info = ~0; /* indicate info not valid */
789 	else
790 		*info = call.ecx;
791 	return APM_SUCCESS;
792 }
793 
794 /**
795  *	set_power_state	-	set the power management state
796  *	@what: which items to transition
797  *	@state: state to transition to
798  *
799  *	Request an APM change of state for one or more system devices. The
800  *	processor state must be transitioned last of all. what holds the
801  *	class of device in the upper byte and the device number (0xFF for
802  *	all) for the object to be transitioned.
803  *
804  *	The state holds the state to transition to, which may in fact
805  *	be an acceptance of a BIOS requested state change.
806  */
807 
808 static int set_power_state(u_short what, u_short state)
809 {
810 	u32 eax;
811 	int err;
812 
813 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
814 		return err;
815 	return APM_SUCCESS;
816 }
817 
818 /**
819  *	set_system_power_state - set system wide power state
820  *	@state: which state to enter
821  *
822  *	Transition the entire system into a new APM power state.
823  */
824 
825 static int set_system_power_state(u_short state)
826 {
827 	return set_power_state(APM_DEVICE_ALL, state);
828 }
829 
830 /**
831  *	apm_do_idle	-	perform power saving
832  *
833  *	This function notifies the BIOS that the processor is (in the view
834  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
835  *	to handle the idle request. On a success the function returns 1
836  *	if the BIOS did clock slowing or 0 otherwise.
837  */
838 
839 static int apm_do_idle(void)
840 {
841 	u32 eax;
842 	u8 ret = 0;
843 	int idled = 0;
844 	int err = 0;
845 
846 	if (!need_resched()) {
847 		idled = 1;
848 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
849 	}
850 
851 	if (!idled)
852 		return 0;
853 
854 	if (ret) {
855 		static unsigned long t;
856 
857 		/* This always fails on some SMP boards running UP kernels.
858 		 * Only report the failure the first 5 times.
859 		 */
860 		if (++t < 5) {
861 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
862 			t = jiffies;
863 		}
864 		return -1;
865 	}
866 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
867 	return clock_slowed;
868 }
869 
870 /**
871  *	apm_do_busy	-	inform the BIOS the CPU is busy
872  *
873  *	Request that the BIOS brings the CPU back to full performance.
874  */
875 
876 static void apm_do_busy(void)
877 {
878 	u32 dummy;
879 	int err;
880 
881 	if (clock_slowed || ALWAYS_CALL_BUSY) {
882 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
883 		clock_slowed = 0;
884 	}
885 }
886 
887 /*
888  * If no process has really been interested in
889  * the CPU for some time, we want to call BIOS
890  * power management - we probably want
891  * to conserve power.
892  */
893 #define IDLE_CALC_LIMIT	(HZ * 100)
894 #define IDLE_LEAKY_MAX	16
895 
896 /**
897  * apm_cpu_idle		-	cpu idling for APM capable Linux
898  *
899  * This is the idling function the kernel executes when APM is available. It
900  * tries to do BIOS powermanagement based on the average system idle time.
901  * Furthermore it calls the system default idle routine.
902  */
903 
904 static int apm_cpu_idle(struct cpuidle_device *dev,
905 	struct cpuidle_driver *drv, int index)
906 {
907 	static int use_apm_idle; /* = 0 */
908 	static unsigned int last_jiffies; /* = 0 */
909 	static u64 last_stime; /* = 0 */
910 	u64 stime, utime;
911 
912 	int apm_idle_done = 0;
913 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
914 	unsigned int bucket;
915 
916 recalc:
917 	task_cputime(current, &utime, &stime);
918 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
919 		use_apm_idle = 0;
920 	} else if (jiffies_since_last_check > idle_period) {
921 		unsigned int idle_percentage;
922 
923 		idle_percentage = nsecs_to_jiffies(stime - last_stime);
924 		idle_percentage *= 100;
925 		idle_percentage /= jiffies_since_last_check;
926 		use_apm_idle = (idle_percentage > idle_threshold);
927 		if (apm_info.forbid_idle)
928 			use_apm_idle = 0;
929 	}
930 
931 	last_jiffies = jiffies;
932 	last_stime = stime;
933 
934 	bucket = IDLE_LEAKY_MAX;
935 
936 	while (!need_resched()) {
937 		if (use_apm_idle) {
938 			unsigned int t;
939 
940 			t = jiffies;
941 			switch (apm_do_idle()) {
942 			case 0:
943 				apm_idle_done = 1;
944 				if (t != jiffies) {
945 					if (bucket) {
946 						bucket = IDLE_LEAKY_MAX;
947 						continue;
948 					}
949 				} else if (bucket) {
950 					bucket--;
951 					continue;
952 				}
953 				break;
954 			case 1:
955 				apm_idle_done = 1;
956 				break;
957 			default: /* BIOS refused */
958 				break;
959 			}
960 		}
961 		default_idle();
962 		local_irq_disable();
963 		jiffies_since_last_check = jiffies - last_jiffies;
964 		if (jiffies_since_last_check > idle_period)
965 			goto recalc;
966 	}
967 
968 	if (apm_idle_done)
969 		apm_do_busy();
970 
971 	return index;
972 }
973 
974 /**
975  *	apm_power_off	-	ask the BIOS to power off
976  *
977  *	Handle the power off sequence. This is the one piece of code we
978  *	will execute even on SMP machines. In order to deal with BIOS
979  *	bugs we support real mode APM BIOS power off calls. We also make
980  *	the SMP call on CPU0 as some systems will only honour this call
981  *	on their first cpu.
982  */
983 
984 static void apm_power_off(void)
985 {
986 	/* Some bioses don't like being called from CPU != 0 */
987 	if (apm_info.realmode_power_off) {
988 		set_cpus_allowed_ptr(current, cpumask_of(0));
989 		machine_real_restart(MRR_APM);
990 	} else {
991 		(void)set_system_power_state(APM_STATE_OFF);
992 	}
993 }
994 
995 #ifdef CONFIG_APM_DO_ENABLE
996 
997 /**
998  *	apm_enable_power_management - enable BIOS APM power management
999  *	@enable: enable yes/no
1000  *
1001  *	Enable or disable the APM BIOS power services.
1002  */
1003 
1004 static int apm_enable_power_management(int enable)
1005 {
1006 	u32 eax;
1007 	int err;
1008 
1009 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1010 		return APM_NOT_ENGAGED;
1011 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1012 				 enable, &eax, &err))
1013 		return err;
1014 	if (enable)
1015 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1016 	else
1017 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1018 	return APM_SUCCESS;
1019 }
1020 #endif
1021 
1022 /**
1023  *	apm_get_power_status	-	get current power state
1024  *	@status: returned status
1025  *	@bat: battery info
1026  *	@life: estimated life
1027  *
1028  *	Obtain the current power status from the APM BIOS. We return a
1029  *	status which gives the rough battery status, and current power
1030  *	source. The bat value returned give an estimate as a percentage
1031  *	of life and a status value for the battery. The estimated life
1032  *	if reported is a lifetime in secodnds/minutes at current powwer
1033  *	consumption.
1034  */
1035 
1036 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1037 {
1038 	struct apm_bios_call call;
1039 
1040 	call.func = APM_FUNC_GET_STATUS;
1041 	call.ebx = APM_DEVICE_ALL;
1042 	call.ecx = 0;
1043 
1044 	if (apm_info.get_power_status_broken)
1045 		return APM_32_UNSUPPORTED;
1046 	if (apm_bios_call(&call)) {
1047 		if (!call.err)
1048 			return APM_NO_ERROR;
1049 		return call.err;
1050 	}
1051 	*status = call.ebx;
1052 	*bat = call.ecx;
1053 	if (apm_info.get_power_status_swabinminutes) {
1054 		*life = swab16((u16)call.edx);
1055 		*life |= 0x8000;
1056 	} else
1057 		*life = call.edx;
1058 	return APM_SUCCESS;
1059 }
1060 
1061 #if 0
1062 static int apm_get_battery_status(u_short which, u_short *status,
1063 				  u_short *bat, u_short *life, u_short *nbat)
1064 {
1065 	u32 eax;
1066 	u32 ebx;
1067 	u32 ecx;
1068 	u32 edx;
1069 	u32 esi;
1070 
1071 	if (apm_info.connection_version < 0x0102) {
1072 		/* pretend we only have one battery. */
1073 		if (which != 1)
1074 			return APM_BAD_DEVICE;
1075 		*nbat = 1;
1076 		return apm_get_power_status(status, bat, life);
1077 	}
1078 
1079 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1080 			  &ebx, &ecx, &edx, &esi))
1081 		return (eax >> 8) & 0xff;
1082 	*status = ebx;
1083 	*bat = ecx;
1084 	*life = edx;
1085 	*nbat = esi;
1086 	return APM_SUCCESS;
1087 }
1088 #endif
1089 
1090 /**
1091  *	apm_engage_power_management	-	enable PM on a device
1092  *	@device: identity of device
1093  *	@enable: on/off
1094  *
1095  *	Activate or deactivate power management on either a specific device
1096  *	or the entire system (%APM_DEVICE_ALL).
1097  */
1098 
1099 static int apm_engage_power_management(u_short device, int enable)
1100 {
1101 	u32 eax;
1102 	int err;
1103 
1104 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1105 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1106 		return APM_DISABLED;
1107 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1108 				 &eax, &err))
1109 		return err;
1110 	if (device == APM_DEVICE_ALL) {
1111 		if (enable)
1112 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1113 		else
1114 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1115 	}
1116 	return APM_SUCCESS;
1117 }
1118 
1119 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1120 
1121 /**
1122  *	apm_console_blank	-	blank the display
1123  *	@blank: on/off
1124  *
1125  *	Attempt to blank the console, firstly by blanking just video device
1126  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1127  *	all video devices. Typically the BIOS will do laptop backlight and
1128  *	monitor powerdown for us.
1129  */
1130 
1131 static int apm_console_blank(int blank)
1132 {
1133 	int error = APM_NOT_ENGAGED; /* silence gcc */
1134 	int i;
1135 	u_short state;
1136 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1137 
1138 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1139 
1140 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1141 		error = set_power_state(dev[i], state);
1142 
1143 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1144 			return 1;
1145 
1146 		if (error == APM_NOT_ENGAGED)
1147 			break;
1148 	}
1149 
1150 	if (error == APM_NOT_ENGAGED) {
1151 		static int tried;
1152 		int eng_error;
1153 		if (tried++ == 0) {
1154 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1155 			if (eng_error) {
1156 				apm_error("set display", error);
1157 				apm_error("engage interface", eng_error);
1158 				return 0;
1159 			} else
1160 				return apm_console_blank(blank);
1161 		}
1162 	}
1163 	apm_error("set display", error);
1164 	return 0;
1165 }
1166 #endif
1167 
1168 static int queue_empty(struct apm_user *as)
1169 {
1170 	return as->event_head == as->event_tail;
1171 }
1172 
1173 static apm_event_t get_queued_event(struct apm_user *as)
1174 {
1175 	if (++as->event_tail >= APM_MAX_EVENTS)
1176 		as->event_tail = 0;
1177 	return as->events[as->event_tail];
1178 }
1179 
1180 static void queue_event(apm_event_t event, struct apm_user *sender)
1181 {
1182 	struct apm_user *as;
1183 
1184 	spin_lock(&user_list_lock);
1185 	if (user_list == NULL)
1186 		goto out;
1187 	for (as = user_list; as != NULL; as = as->next) {
1188 		if ((as == sender) || (!as->reader))
1189 			continue;
1190 		if (++as->event_head >= APM_MAX_EVENTS)
1191 			as->event_head = 0;
1192 
1193 		if (as->event_head == as->event_tail) {
1194 			static int notified;
1195 
1196 			if (notified++ == 0)
1197 				pr_err("an event queue overflowed\n");
1198 			if (++as->event_tail >= APM_MAX_EVENTS)
1199 				as->event_tail = 0;
1200 		}
1201 		as->events[as->event_head] = event;
1202 		if (!as->suser || !as->writer)
1203 			continue;
1204 		switch (event) {
1205 		case APM_SYS_SUSPEND:
1206 		case APM_USER_SUSPEND:
1207 			as->suspends_pending++;
1208 			suspends_pending++;
1209 			break;
1210 
1211 		case APM_SYS_STANDBY:
1212 		case APM_USER_STANDBY:
1213 			as->standbys_pending++;
1214 			standbys_pending++;
1215 			break;
1216 		}
1217 	}
1218 	wake_up_interruptible(&apm_waitqueue);
1219 out:
1220 	spin_unlock(&user_list_lock);
1221 }
1222 
1223 static void reinit_timer(void)
1224 {
1225 #ifdef INIT_TIMER_AFTER_SUSPEND
1226 	unsigned long flags;
1227 
1228 	raw_spin_lock_irqsave(&i8253_lock, flags);
1229 	/* set the clock to HZ */
1230 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1231 	udelay(10);
1232 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1233 	udelay(10);
1234 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1235 	udelay(10);
1236 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1237 #endif
1238 }
1239 
1240 static int suspend(int vetoable)
1241 {
1242 	int err;
1243 	struct apm_user	*as;
1244 
1245 	dpm_suspend_start(PMSG_SUSPEND);
1246 	dpm_suspend_end(PMSG_SUSPEND);
1247 
1248 	local_irq_disable();
1249 	syscore_suspend();
1250 
1251 	local_irq_enable();
1252 
1253 	save_processor_state();
1254 	err = set_system_power_state(APM_STATE_SUSPEND);
1255 	ignore_normal_resume = 1;
1256 	restore_processor_state();
1257 
1258 	local_irq_disable();
1259 	reinit_timer();
1260 
1261 	if (err == APM_NO_ERROR)
1262 		err = APM_SUCCESS;
1263 	if (err != APM_SUCCESS)
1264 		apm_error("suspend", err);
1265 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1266 
1267 	syscore_resume();
1268 	local_irq_enable();
1269 
1270 	dpm_resume_start(PMSG_RESUME);
1271 	dpm_resume_end(PMSG_RESUME);
1272 
1273 	queue_event(APM_NORMAL_RESUME, NULL);
1274 	spin_lock(&user_list_lock);
1275 	for (as = user_list; as != NULL; as = as->next) {
1276 		as->suspend_wait = 0;
1277 		as->suspend_result = err;
1278 	}
1279 	spin_unlock(&user_list_lock);
1280 	wake_up_interruptible(&apm_suspend_waitqueue);
1281 	return err;
1282 }
1283 
1284 static void standby(void)
1285 {
1286 	int err;
1287 
1288 	dpm_suspend_end(PMSG_SUSPEND);
1289 
1290 	local_irq_disable();
1291 	syscore_suspend();
1292 	local_irq_enable();
1293 
1294 	err = set_system_power_state(APM_STATE_STANDBY);
1295 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1296 		apm_error("standby", err);
1297 
1298 	local_irq_disable();
1299 	syscore_resume();
1300 	local_irq_enable();
1301 
1302 	dpm_resume_start(PMSG_RESUME);
1303 }
1304 
1305 static apm_event_t get_event(void)
1306 {
1307 	int error;
1308 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1309 	apm_eventinfo_t	info;
1310 
1311 	static int notified;
1312 
1313 	/* we don't use the eventinfo */
1314 	error = apm_get_event(&event, &info);
1315 	if (error == APM_SUCCESS)
1316 		return event;
1317 
1318 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1319 		apm_error("get_event", error);
1320 
1321 	return 0;
1322 }
1323 
1324 static void check_events(void)
1325 {
1326 	apm_event_t event;
1327 	static unsigned long last_resume;
1328 	static int ignore_bounce;
1329 
1330 	while ((event = get_event()) != 0) {
1331 		if (debug) {
1332 			if (event <= NR_APM_EVENT_NAME)
1333 				printk(KERN_DEBUG "apm: received %s notify\n",
1334 				       apm_event_name[event - 1]);
1335 			else
1336 				printk(KERN_DEBUG "apm: received unknown "
1337 				       "event 0x%02x\n", event);
1338 		}
1339 		if (ignore_bounce
1340 		    && (time_after(jiffies, last_resume + bounce_interval)))
1341 			ignore_bounce = 0;
1342 
1343 		switch (event) {
1344 		case APM_SYS_STANDBY:
1345 		case APM_USER_STANDBY:
1346 			queue_event(event, NULL);
1347 			if (standbys_pending <= 0)
1348 				standby();
1349 			break;
1350 
1351 		case APM_USER_SUSPEND:
1352 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1353 			if (apm_info.connection_version > 0x100)
1354 				set_system_power_state(APM_STATE_REJECT);
1355 			break;
1356 #endif
1357 		case APM_SYS_SUSPEND:
1358 			if (ignore_bounce) {
1359 				if (apm_info.connection_version > 0x100)
1360 					set_system_power_state(APM_STATE_REJECT);
1361 				break;
1362 			}
1363 			/*
1364 			 * If we are already processing a SUSPEND,
1365 			 * then further SUSPEND events from the BIOS
1366 			 * will be ignored.  We also return here to
1367 			 * cope with the fact that the Thinkpads keep
1368 			 * sending a SUSPEND event until something else
1369 			 * happens!
1370 			 */
1371 			if (ignore_sys_suspend)
1372 				return;
1373 			ignore_sys_suspend = 1;
1374 			queue_event(event, NULL);
1375 			if (suspends_pending <= 0)
1376 				(void) suspend(1);
1377 			break;
1378 
1379 		case APM_NORMAL_RESUME:
1380 		case APM_CRITICAL_RESUME:
1381 		case APM_STANDBY_RESUME:
1382 			ignore_sys_suspend = 0;
1383 			last_resume = jiffies;
1384 			ignore_bounce = 1;
1385 			if ((event != APM_NORMAL_RESUME)
1386 			    || (ignore_normal_resume == 0)) {
1387 				dpm_resume_end(PMSG_RESUME);
1388 				queue_event(event, NULL);
1389 			}
1390 			ignore_normal_resume = 0;
1391 			break;
1392 
1393 		case APM_CAPABILITY_CHANGE:
1394 		case APM_LOW_BATTERY:
1395 		case APM_POWER_STATUS_CHANGE:
1396 			queue_event(event, NULL);
1397 			/* If needed, notify drivers here */
1398 			break;
1399 
1400 		case APM_UPDATE_TIME:
1401 			break;
1402 
1403 		case APM_CRITICAL_SUSPEND:
1404 			/*
1405 			 * We are not allowed to reject a critical suspend.
1406 			 */
1407 			(void)suspend(0);
1408 			break;
1409 		}
1410 	}
1411 }
1412 
1413 static void apm_event_handler(void)
1414 {
1415 	static int pending_count = 4;
1416 	int err;
1417 
1418 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1419 		if ((apm_info.connection_version > 0x100) &&
1420 		    (pending_count-- <= 0)) {
1421 			pending_count = 4;
1422 			if (debug)
1423 				printk(KERN_DEBUG "apm: setting state busy\n");
1424 			err = set_system_power_state(APM_STATE_BUSY);
1425 			if (err)
1426 				apm_error("busy", err);
1427 		}
1428 	} else
1429 		pending_count = 4;
1430 	check_events();
1431 }
1432 
1433 /*
1434  * This is the APM thread main loop.
1435  */
1436 
1437 static void apm_mainloop(void)
1438 {
1439 	DECLARE_WAITQUEUE(wait, current);
1440 
1441 	add_wait_queue(&apm_waitqueue, &wait);
1442 	set_current_state(TASK_INTERRUPTIBLE);
1443 	for (;;) {
1444 		schedule_timeout(APM_CHECK_TIMEOUT);
1445 		if (kthread_should_stop())
1446 			break;
1447 		/*
1448 		 * Ok, check all events, check for idle (and mark us sleeping
1449 		 * so as not to count towards the load average)..
1450 		 */
1451 		set_current_state(TASK_INTERRUPTIBLE);
1452 		apm_event_handler();
1453 	}
1454 	remove_wait_queue(&apm_waitqueue, &wait);
1455 }
1456 
1457 static int check_apm_user(struct apm_user *as, const char *func)
1458 {
1459 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1460 		pr_err("%s passed bad filp\n", func);
1461 		return 1;
1462 	}
1463 	return 0;
1464 }
1465 
1466 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1467 {
1468 	struct apm_user *as;
1469 	int i;
1470 	apm_event_t event;
1471 
1472 	as = fp->private_data;
1473 	if (check_apm_user(as, "read"))
1474 		return -EIO;
1475 	if ((int)count < sizeof(apm_event_t))
1476 		return -EINVAL;
1477 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1478 		return -EAGAIN;
1479 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1480 	i = count;
1481 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1482 		event = get_queued_event(as);
1483 		if (copy_to_user(buf, &event, sizeof(event))) {
1484 			if (i < count)
1485 				break;
1486 			return -EFAULT;
1487 		}
1488 		switch (event) {
1489 		case APM_SYS_SUSPEND:
1490 		case APM_USER_SUSPEND:
1491 			as->suspends_read++;
1492 			break;
1493 
1494 		case APM_SYS_STANDBY:
1495 		case APM_USER_STANDBY:
1496 			as->standbys_read++;
1497 			break;
1498 		}
1499 		buf += sizeof(event);
1500 		i -= sizeof(event);
1501 	}
1502 	if (i < count)
1503 		return count - i;
1504 	if (signal_pending(current))
1505 		return -ERESTARTSYS;
1506 	return 0;
1507 }
1508 
1509 static __poll_t do_poll(struct file *fp, poll_table *wait)
1510 {
1511 	struct apm_user *as;
1512 
1513 	as = fp->private_data;
1514 	if (check_apm_user(as, "poll"))
1515 		return 0;
1516 	poll_wait(fp, &apm_waitqueue, wait);
1517 	if (!queue_empty(as))
1518 		return EPOLLIN | EPOLLRDNORM;
1519 	return 0;
1520 }
1521 
1522 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1523 {
1524 	struct apm_user *as;
1525 	int ret;
1526 
1527 	as = filp->private_data;
1528 	if (check_apm_user(as, "ioctl"))
1529 		return -EIO;
1530 	if (!as->suser || !as->writer)
1531 		return -EPERM;
1532 	switch (cmd) {
1533 	case APM_IOC_STANDBY:
1534 		mutex_lock(&apm_mutex);
1535 		if (as->standbys_read > 0) {
1536 			as->standbys_read--;
1537 			as->standbys_pending--;
1538 			standbys_pending--;
1539 		} else
1540 			queue_event(APM_USER_STANDBY, as);
1541 		if (standbys_pending <= 0)
1542 			standby();
1543 		mutex_unlock(&apm_mutex);
1544 		break;
1545 	case APM_IOC_SUSPEND:
1546 		mutex_lock(&apm_mutex);
1547 		if (as->suspends_read > 0) {
1548 			as->suspends_read--;
1549 			as->suspends_pending--;
1550 			suspends_pending--;
1551 		} else
1552 			queue_event(APM_USER_SUSPEND, as);
1553 		if (suspends_pending <= 0) {
1554 			ret = suspend(1);
1555 			mutex_unlock(&apm_mutex);
1556 		} else {
1557 			as->suspend_wait = 1;
1558 			mutex_unlock(&apm_mutex);
1559 			wait_event_interruptible(apm_suspend_waitqueue,
1560 					as->suspend_wait == 0);
1561 			ret = as->suspend_result;
1562 		}
1563 		return ret;
1564 	default:
1565 		return -ENOTTY;
1566 	}
1567 	return 0;
1568 }
1569 
1570 static int do_release(struct inode *inode, struct file *filp)
1571 {
1572 	struct apm_user *as;
1573 
1574 	as = filp->private_data;
1575 	if (check_apm_user(as, "release"))
1576 		return 0;
1577 	filp->private_data = NULL;
1578 	if (as->standbys_pending > 0) {
1579 		standbys_pending -= as->standbys_pending;
1580 		if (standbys_pending <= 0)
1581 			standby();
1582 	}
1583 	if (as->suspends_pending > 0) {
1584 		suspends_pending -= as->suspends_pending;
1585 		if (suspends_pending <= 0)
1586 			(void) suspend(1);
1587 	}
1588 	spin_lock(&user_list_lock);
1589 	if (user_list == as)
1590 		user_list = as->next;
1591 	else {
1592 		struct apm_user *as1;
1593 
1594 		for (as1 = user_list;
1595 		     (as1 != NULL) && (as1->next != as);
1596 		     as1 = as1->next)
1597 			;
1598 		if (as1 == NULL)
1599 			pr_err("filp not in user list\n");
1600 		else
1601 			as1->next = as->next;
1602 	}
1603 	spin_unlock(&user_list_lock);
1604 	kfree(as);
1605 	return 0;
1606 }
1607 
1608 static int do_open(struct inode *inode, struct file *filp)
1609 {
1610 	struct apm_user *as;
1611 
1612 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1613 	if (as == NULL)
1614 		return -ENOMEM;
1615 
1616 	as->magic = APM_BIOS_MAGIC;
1617 	as->event_tail = as->event_head = 0;
1618 	as->suspends_pending = as->standbys_pending = 0;
1619 	as->suspends_read = as->standbys_read = 0;
1620 	/*
1621 	 * XXX - this is a tiny bit broken, when we consider BSD
1622 	 * process accounting. If the device is opened by root, we
1623 	 * instantly flag that we used superuser privs. Who knows,
1624 	 * we might close the device immediately without doing a
1625 	 * privileged operation -- cevans
1626 	 */
1627 	as->suser = capable(CAP_SYS_ADMIN);
1628 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1629 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1630 	spin_lock(&user_list_lock);
1631 	as->next = user_list;
1632 	user_list = as;
1633 	spin_unlock(&user_list_lock);
1634 	filp->private_data = as;
1635 	return 0;
1636 }
1637 
1638 static int proc_apm_show(struct seq_file *m, void *v)
1639 {
1640 	unsigned short	bx;
1641 	unsigned short	cx;
1642 	unsigned short	dx;
1643 	int		error;
1644 	unsigned short  ac_line_status = 0xff;
1645 	unsigned short  battery_status = 0xff;
1646 	unsigned short  battery_flag   = 0xff;
1647 	int		percentage     = -1;
1648 	int             time_units     = -1;
1649 	char            *units         = "?";
1650 
1651 	if ((num_online_cpus() == 1) &&
1652 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1653 		ac_line_status = (bx >> 8) & 0xff;
1654 		battery_status = bx & 0xff;
1655 		if ((cx & 0xff) != 0xff)
1656 			percentage = cx & 0xff;
1657 
1658 		if (apm_info.connection_version > 0x100) {
1659 			battery_flag = (cx >> 8) & 0xff;
1660 			if (dx != 0xffff) {
1661 				units = (dx & 0x8000) ? "min" : "sec";
1662 				time_units = dx & 0x7fff;
1663 			}
1664 		}
1665 	}
1666 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1667 	   from the Get Power Status (0x0a) call unless otherwise noted.
1668 
1669 	   0) Linux driver version (this will change if format changes)
1670 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1671 	   2) APM flags from APM Installation Check (0x00):
1672 	      bit 0: APM_16_BIT_SUPPORT
1673 	      bit 1: APM_32_BIT_SUPPORT
1674 	      bit 2: APM_IDLE_SLOWS_CLOCK
1675 	      bit 3: APM_BIOS_DISABLED
1676 	      bit 4: APM_BIOS_DISENGAGED
1677 	   3) AC line status
1678 	      0x00: Off-line
1679 	      0x01: On-line
1680 	      0x02: On backup power (BIOS >= 1.1 only)
1681 	      0xff: Unknown
1682 	   4) Battery status
1683 	      0x00: High
1684 	      0x01: Low
1685 	      0x02: Critical
1686 	      0x03: Charging
1687 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1688 	      0xff: Unknown
1689 	   5) Battery flag
1690 	      bit 0: High
1691 	      bit 1: Low
1692 	      bit 2: Critical
1693 	      bit 3: Charging
1694 	      bit 7: No system battery
1695 	      0xff: Unknown
1696 	   6) Remaining battery life (percentage of charge):
1697 	      0-100: valid
1698 	      -1: Unknown
1699 	   7) Remaining battery life (time units):
1700 	      Number of remaining minutes or seconds
1701 	      -1: Unknown
1702 	   8) min = minutes; sec = seconds */
1703 
1704 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1705 		   driver_version,
1706 		   (apm_info.bios.version >> 8) & 0xff,
1707 		   apm_info.bios.version & 0xff,
1708 		   apm_info.bios.flags,
1709 		   ac_line_status,
1710 		   battery_status,
1711 		   battery_flag,
1712 		   percentage,
1713 		   time_units,
1714 		   units);
1715 	return 0;
1716 }
1717 
1718 static int apm(void *unused)
1719 {
1720 	unsigned short	bx;
1721 	unsigned short	cx;
1722 	unsigned short	dx;
1723 	int		error;
1724 	char 		*power_stat;
1725 	char 		*bat_stat;
1726 
1727 	/* 2002/08/01 - WT
1728 	 * This is to avoid random crashes at boot time during initialization
1729 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1730 	 * Some bioses don't like being called from CPU != 0.
1731 	 * Method suggested by Ingo Molnar.
1732 	 */
1733 	set_cpus_allowed_ptr(current, cpumask_of(0));
1734 	BUG_ON(smp_processor_id() != 0);
1735 
1736 	if (apm_info.connection_version == 0) {
1737 		apm_info.connection_version = apm_info.bios.version;
1738 		if (apm_info.connection_version > 0x100) {
1739 			/*
1740 			 * We only support BIOSs up to version 1.2
1741 			 */
1742 			if (apm_info.connection_version > 0x0102)
1743 				apm_info.connection_version = 0x0102;
1744 			error = apm_driver_version(&apm_info.connection_version);
1745 			if (error != APM_SUCCESS) {
1746 				apm_error("driver version", error);
1747 				/* Fall back to an APM 1.0 connection. */
1748 				apm_info.connection_version = 0x100;
1749 			}
1750 		}
1751 	}
1752 
1753 	if (debug)
1754 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1755 			(apm_info.connection_version >> 8) & 0xff,
1756 			apm_info.connection_version & 0xff);
1757 
1758 #ifdef CONFIG_APM_DO_ENABLE
1759 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1760 		/*
1761 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1762 		 * is booted with PM disabled but not in the docking station.
1763 		 * Unfortunate ...
1764 		 */
1765 		error = apm_enable_power_management(1);
1766 		if (error) {
1767 			apm_error("enable power management", error);
1768 			return -1;
1769 		}
1770 	}
1771 #endif
1772 
1773 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1774 	    && (apm_info.connection_version > 0x0100)) {
1775 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1776 		if (error) {
1777 			apm_error("engage power management", error);
1778 			return -1;
1779 		}
1780 	}
1781 
1782 	if (debug && (num_online_cpus() == 1 || smp)) {
1783 		error = apm_get_power_status(&bx, &cx, &dx);
1784 		if (error)
1785 			printk(KERN_INFO "apm: power status not available\n");
1786 		else {
1787 			switch ((bx >> 8) & 0xff) {
1788 			case 0:
1789 				power_stat = "off line";
1790 				break;
1791 			case 1:
1792 				power_stat = "on line";
1793 				break;
1794 			case 2:
1795 				power_stat = "on backup power";
1796 				break;
1797 			default:
1798 				power_stat = "unknown";
1799 				break;
1800 			}
1801 			switch (bx & 0xff) {
1802 			case 0:
1803 				bat_stat = "high";
1804 				break;
1805 			case 1:
1806 				bat_stat = "low";
1807 				break;
1808 			case 2:
1809 				bat_stat = "critical";
1810 				break;
1811 			case 3:
1812 				bat_stat = "charging";
1813 				break;
1814 			default:
1815 				bat_stat = "unknown";
1816 				break;
1817 			}
1818 			printk(KERN_INFO
1819 			       "apm: AC %s, battery status %s, battery life ",
1820 			       power_stat, bat_stat);
1821 			if ((cx & 0xff) == 0xff)
1822 				printk("unknown\n");
1823 			else
1824 				printk("%d%%\n", cx & 0xff);
1825 			if (apm_info.connection_version > 0x100) {
1826 				printk(KERN_INFO
1827 				       "apm: battery flag 0x%02x, battery life ",
1828 				       (cx >> 8) & 0xff);
1829 				if (dx == 0xffff)
1830 					printk("unknown\n");
1831 				else
1832 					printk("%d %s\n", dx & 0x7fff,
1833 					       (dx & 0x8000) ?
1834 					       "minutes" : "seconds");
1835 			}
1836 		}
1837 	}
1838 
1839 	/* Install our power off handler.. */
1840 	if (power_off)
1841 		pm_power_off = apm_power_off;
1842 
1843 	if (num_online_cpus() == 1 || smp) {
1844 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1845 		console_blank_hook = apm_console_blank;
1846 #endif
1847 		apm_mainloop();
1848 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1849 		console_blank_hook = NULL;
1850 #endif
1851 	}
1852 
1853 	return 0;
1854 }
1855 
1856 #ifndef MODULE
1857 static int __init apm_setup(char *str)
1858 {
1859 	int invert;
1860 
1861 	while ((str != NULL) && (*str != '\0')) {
1862 		if (strncmp(str, "off", 3) == 0)
1863 			apm_disabled = 1;
1864 		if (strncmp(str, "on", 2) == 0)
1865 			apm_disabled = 0;
1866 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1867 		    (strncmp(str, "bounce_interval=", 16) == 0))
1868 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1869 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1870 		    (strncmp(str, "idle_threshold=", 15) == 0))
1871 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1872 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1873 		    (strncmp(str, "idle_period=", 12) == 0))
1874 			idle_period = simple_strtol(str + 12, NULL, 0);
1875 		invert = (strncmp(str, "no-", 3) == 0) ||
1876 			(strncmp(str, "no_", 3) == 0);
1877 		if (invert)
1878 			str += 3;
1879 		if (strncmp(str, "debug", 5) == 0)
1880 			debug = !invert;
1881 		if ((strncmp(str, "power-off", 9) == 0) ||
1882 		    (strncmp(str, "power_off", 9) == 0))
1883 			power_off = !invert;
1884 		if (strncmp(str, "smp", 3) == 0) {
1885 			smp = !invert;
1886 			idle_threshold = 100;
1887 		}
1888 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1889 		    (strncmp(str, "allow_ints", 10) == 0))
1890 			apm_info.allow_ints = !invert;
1891 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1892 		    (strncmp(str, "broken_psr", 10) == 0))
1893 			apm_info.get_power_status_broken = !invert;
1894 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1895 		    (strncmp(str, "realmode_power_off", 18) == 0))
1896 			apm_info.realmode_power_off = !invert;
1897 		str = strchr(str, ',');
1898 		if (str != NULL)
1899 			str += strspn(str, ", \t");
1900 	}
1901 	return 1;
1902 }
1903 
1904 __setup("apm=", apm_setup);
1905 #endif
1906 
1907 static const struct file_operations apm_bios_fops = {
1908 	.owner		= THIS_MODULE,
1909 	.read		= do_read,
1910 	.poll		= do_poll,
1911 	.unlocked_ioctl	= do_ioctl,
1912 	.open		= do_open,
1913 	.release	= do_release,
1914 	.llseek		= noop_llseek,
1915 };
1916 
1917 static struct miscdevice apm_device = {
1918 	APM_MINOR_DEV,
1919 	"apm_bios",
1920 	&apm_bios_fops
1921 };
1922 
1923 
1924 /* Simple "print if true" callback */
1925 static int __init print_if_true(const struct dmi_system_id *d)
1926 {
1927 	printk("%s\n", d->ident);
1928 	return 0;
1929 }
1930 
1931 /*
1932  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1933  * disabled before the suspend. Linux used to get terribly confused by that.
1934  */
1935 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1936 {
1937 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1938 	       "workaround hopefully not needed.\n", d->ident);
1939 	return 0;
1940 }
1941 
1942 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1943 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1944 {
1945 	if (apm_info.realmode_power_off == 0) {
1946 		apm_info.realmode_power_off = 1;
1947 		printk(KERN_INFO "%s bios detected. "
1948 		       "Using realmode poweroff only.\n", d->ident);
1949 	}
1950 	return 0;
1951 }
1952 
1953 /* Some laptops require interrupts to be enabled during APM calls */
1954 static int __init set_apm_ints(const struct dmi_system_id *d)
1955 {
1956 	if (apm_info.allow_ints == 0) {
1957 		apm_info.allow_ints = 1;
1958 		printk(KERN_INFO "%s machine detected. "
1959 		       "Enabling interrupts during APM calls.\n", d->ident);
1960 	}
1961 	return 0;
1962 }
1963 
1964 /* Some APM bioses corrupt memory or just plain do not work */
1965 static int __init apm_is_horked(const struct dmi_system_id *d)
1966 {
1967 	if (apm_info.disabled == 0) {
1968 		apm_info.disabled = 1;
1969 		printk(KERN_INFO "%s machine detected. "
1970 		       "Disabling APM.\n", d->ident);
1971 	}
1972 	return 0;
1973 }
1974 
1975 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1976 {
1977 	if (apm_info.disabled == 0) {
1978 		apm_info.disabled = 1;
1979 		printk(KERN_INFO "%s machine detected. "
1980 		       "Disabling APM.\n", d->ident);
1981 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1982 		printk(KERN_INFO "download from support.intel.com\n");
1983 	}
1984 	return 0;
1985 }
1986 
1987 /* Some APM bioses hang on APM idle calls */
1988 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1989 {
1990 	if (apm_info.forbid_idle == 0) {
1991 		apm_info.forbid_idle = 1;
1992 		printk(KERN_INFO "%s machine detected. "
1993 		       "Disabling APM idle calls.\n", d->ident);
1994 	}
1995 	return 0;
1996 }
1997 
1998 /*
1999  *  Check for clue free BIOS implementations who use
2000  *  the following QA technique
2001  *
2002  *      [ Write BIOS Code ]<------
2003  *               |                ^
2004  *      < Does it Compile >----N--
2005  *               |Y               ^
2006  *	< Does it Boot Win98 >-N--
2007  *               |Y
2008  *           [Ship It]
2009  *
2010  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2011  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2012  */
2013 static int __init broken_apm_power(const struct dmi_system_id *d)
2014 {
2015 	apm_info.get_power_status_broken = 1;
2016 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2017 	       "disabling power status reporting.\n");
2018 	return 0;
2019 }
2020 
2021 /*
2022  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2023  * have this problem).
2024  */
2025 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2026 {
2027 	apm_info.get_power_status_swabinminutes = 1;
2028 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2029 	       "in minutes and wrong byte order.\n");
2030 	return 0;
2031 }
2032 
2033 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2034 	{
2035 		print_if_true,
2036 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2037 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2038 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2039 	},
2040 	{	/* Handle problems with APM on the C600 */
2041 		broken_ps2_resume, "Dell Latitude C600",
2042 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2043 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2044 	},
2045 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2046 		set_apm_ints, "Dell Latitude",
2047 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2048 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2049 	},
2050 	{	/* APM crashes */
2051 		apm_is_horked, "Dell Inspiron 2500",
2052 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2053 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2054 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2055 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2056 	},
2057 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2058 		set_apm_ints, "Dell Inspiron", {
2059 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2060 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2061 	},
2062 	{	/* Handle problems with APM on Inspiron 5000e */
2063 		broken_apm_power, "Dell Inspiron 5000e",
2064 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2065 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2066 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2067 	},
2068 	{	/* Handle problems with APM on Inspiron 2500 */
2069 		broken_apm_power, "Dell Inspiron 2500",
2070 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2071 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2072 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2073 	},
2074 	{	/* APM crashes */
2075 		apm_is_horked, "Dell Dimension 4100",
2076 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2077 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2078 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2079 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2080 	},
2081 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2082 		set_apm_ints, "Compaq 12XL125",
2083 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2084 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2085 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2086 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2087 	},
2088 	{	/* Allow interrupts during APM or the clock goes slow */
2089 		set_apm_ints, "ASUSTeK",
2090 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2091 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2092 	},
2093 	{	/* APM blows on shutdown */
2094 		apm_is_horked, "ABIT KX7-333[R]",
2095 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2096 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2097 	},
2098 	{	/* APM crashes */
2099 		apm_is_horked, "Trigem Delhi3",
2100 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2101 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2102 	},
2103 	{	/* APM crashes */
2104 		apm_is_horked, "Fujitsu-Siemens",
2105 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2106 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2107 	},
2108 	{	/* APM crashes */
2109 		apm_is_horked_d850md, "Intel D850MD",
2110 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2111 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2112 	},
2113 	{	/* APM crashes */
2114 		apm_is_horked, "Intel D810EMO",
2115 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2116 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2117 	},
2118 	{	/* APM crashes */
2119 		apm_is_horked, "Dell XPS-Z",
2120 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2121 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2122 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2123 	},
2124 	{	/* APM crashes */
2125 		apm_is_horked, "Sharp PC-PJ/AX",
2126 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2127 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2128 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2129 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2130 	},
2131 	{	/* APM crashes */
2132 		apm_is_horked, "Dell Inspiron 2500",
2133 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2134 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2135 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2136 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2137 	},
2138 	{	/* APM idle hangs */
2139 		apm_likes_to_melt, "Jabil AMD",
2140 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2141 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2142 	},
2143 	{	/* APM idle hangs */
2144 		apm_likes_to_melt, "AMI Bios",
2145 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2146 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2147 	},
2148 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2149 		swab_apm_power_in_minutes, "Sony VAIO",
2150 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2151 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2152 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2153 	},
2154 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2155 		swab_apm_power_in_minutes, "Sony VAIO",
2156 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2157 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2158 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2159 	},
2160 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2161 		swab_apm_power_in_minutes, "Sony VAIO",
2162 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2163 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2164 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2165 	},
2166 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2167 		swab_apm_power_in_minutes, "Sony VAIO",
2168 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2169 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2170 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2171 	},
2172 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2173 		swab_apm_power_in_minutes, "Sony VAIO",
2174 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2175 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2176 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2177 	},
2178 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2179 		swab_apm_power_in_minutes, "Sony VAIO",
2180 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2181 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2182 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2183 	},
2184 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2185 		swab_apm_power_in_minutes, "Sony VAIO",
2186 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2187 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2188 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2189 	},
2190 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2191 		swab_apm_power_in_minutes, "Sony VAIO",
2192 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2193 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2194 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2195 	},
2196 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2197 		swab_apm_power_in_minutes, "Sony VAIO",
2198 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2199 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2200 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2201 	},
2202 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2203 		swab_apm_power_in_minutes, "Sony VAIO",
2204 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2205 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2206 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2207 	},
2208 
2209 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2210 		swab_apm_power_in_minutes, "Sony VAIO",
2211 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2212 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2213 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2214 	},
2215 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2216 		swab_apm_power_in_minutes, "Sony VAIO",
2217 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2218 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2219 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2220 	},
2221 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2222 		swab_apm_power_in_minutes, "Sony VAIO",
2223 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2224 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2225 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2226 	},
2227 	{	/* broken PM poweroff bios */
2228 		set_realmode_power_off, "Award Software v4.60 PGMA",
2229 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2230 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2231 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2232 	},
2233 
2234 	/* Generic per vendor APM settings  */
2235 
2236 	{	/* Allow interrupts during suspend on IBM laptops */
2237 		set_apm_ints, "IBM",
2238 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2239 	},
2240 
2241 	{ }
2242 };
2243 
2244 /*
2245  * Just start the APM thread. We do NOT want to do APM BIOS
2246  * calls from anything but the APM thread, if for no other reason
2247  * than the fact that we don't trust the APM BIOS. This way,
2248  * most common APM BIOS problems that lead to protection errors
2249  * etc will have at least some level of being contained...
2250  *
2251  * In short, if something bad happens, at least we have a choice
2252  * of just killing the apm thread..
2253  */
2254 static int __init apm_init(void)
2255 {
2256 	struct desc_struct *gdt;
2257 	int err;
2258 
2259 	dmi_check_system(apm_dmi_table);
2260 
2261 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2262 		printk(KERN_INFO "apm: BIOS not found.\n");
2263 		return -ENODEV;
2264 	}
2265 	printk(KERN_INFO
2266 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2267 	       ((apm_info.bios.version >> 8) & 0xff),
2268 	       (apm_info.bios.version & 0xff),
2269 	       apm_info.bios.flags,
2270 	       driver_version);
2271 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2272 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2273 		return -ENODEV;
2274 	}
2275 
2276 	if (allow_ints)
2277 		apm_info.allow_ints = 1;
2278 	if (broken_psr)
2279 		apm_info.get_power_status_broken = 1;
2280 	if (realmode_power_off)
2281 		apm_info.realmode_power_off = 1;
2282 	/* User can override, but default is to trust DMI */
2283 	if (apm_disabled != -1)
2284 		apm_info.disabled = apm_disabled;
2285 
2286 	/*
2287 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2288 	 * but is reportedly a 1.0 BIOS.
2289 	 */
2290 	if (apm_info.bios.version == 0x001)
2291 		apm_info.bios.version = 0x100;
2292 
2293 	/* BIOS < 1.2 doesn't set cseg_16_len */
2294 	if (apm_info.bios.version < 0x102)
2295 		apm_info.bios.cseg_16_len = 0; /* 64k */
2296 
2297 	if (debug) {
2298 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2299 			apm_info.bios.cseg, apm_info.bios.offset,
2300 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2301 		if (apm_info.bios.version > 0x100)
2302 			printk(" cseg len %x, dseg len %x",
2303 				apm_info.bios.cseg_len,
2304 				apm_info.bios.dseg_len);
2305 		if (apm_info.bios.version > 0x101)
2306 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2307 		printk("\n");
2308 	}
2309 
2310 	if (apm_info.disabled) {
2311 		pr_notice("disabled on user request.\n");
2312 		return -ENODEV;
2313 	}
2314 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2315 		pr_notice("disabled - APM is not SMP safe.\n");
2316 		apm_info.disabled = 1;
2317 		return -ENODEV;
2318 	}
2319 	if (!acpi_disabled) {
2320 		pr_notice("overridden by ACPI.\n");
2321 		apm_info.disabled = 1;
2322 		return -ENODEV;
2323 	}
2324 
2325 	/*
2326 	 * Set up the long jump entry point to the APM BIOS, which is called
2327 	 * from inline assembly.
2328 	 */
2329 	apm_bios_entry.offset = apm_info.bios.offset;
2330 	apm_bios_entry.segment = APM_CS;
2331 
2332 	/*
2333 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2334 	 * recognizes.  Many machines do this correctly, but many others do
2335 	 * not restrict themselves to their claimed limit.  When this happens,
2336 	 * they will cause a segmentation violation in the kernel at boot time.
2337 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2338 	 *
2339 	 * Note we only set APM segments on CPU zero, since we pin the APM
2340 	 * code to that CPU.
2341 	 */
2342 	gdt = get_cpu_gdt_rw(0);
2343 	set_desc_base(&gdt[APM_CS >> 3],
2344 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2345 	set_desc_base(&gdt[APM_CS_16 >> 3],
2346 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2347 	set_desc_base(&gdt[APM_DS >> 3],
2348 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2349 
2350 	proc_create_single("apm", 0, NULL, proc_apm_show);
2351 
2352 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2353 	if (IS_ERR(kapmd_task)) {
2354 		pr_err("disabled - Unable to start kernel thread\n");
2355 		err = PTR_ERR(kapmd_task);
2356 		kapmd_task = NULL;
2357 		remove_proc_entry("apm", NULL);
2358 		return err;
2359 	}
2360 	wake_up_process(kapmd_task);
2361 
2362 	if (num_online_cpus() > 1 && !smp) {
2363 		printk(KERN_NOTICE
2364 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2365 		return 0;
2366 	}
2367 
2368 	/*
2369 	 * Note we don't actually care if the misc_device cannot be registered.
2370 	 * this driver can do its job without it, even if userspace can't
2371 	 * control it.  just log the error
2372 	 */
2373 	if (misc_register(&apm_device))
2374 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2375 
2376 	if (HZ != 100)
2377 		idle_period = (idle_period * HZ) / 100;
2378 	if (idle_threshold < 100) {
2379 		cpuidle_poll_state_init(&apm_idle_driver);
2380 		if (!cpuidle_register_driver(&apm_idle_driver))
2381 			if (cpuidle_register_device(&apm_cpuidle_device))
2382 				cpuidle_unregister_driver(&apm_idle_driver);
2383 	}
2384 
2385 	return 0;
2386 }
2387 
2388 static void __exit apm_exit(void)
2389 {
2390 	int error;
2391 
2392 	cpuidle_unregister_device(&apm_cpuidle_device);
2393 	cpuidle_unregister_driver(&apm_idle_driver);
2394 
2395 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2396 	    && (apm_info.connection_version > 0x0100)) {
2397 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2398 		if (error)
2399 			apm_error("disengage power management", error);
2400 	}
2401 	misc_deregister(&apm_device);
2402 	remove_proc_entry("apm", NULL);
2403 	if (power_off)
2404 		pm_power_off = NULL;
2405 	if (kapmd_task) {
2406 		kthread_stop(kapmd_task);
2407 		kapmd_task = NULL;
2408 	}
2409 }
2410 
2411 module_init(apm_init);
2412 module_exit(apm_exit);
2413 
2414 MODULE_AUTHOR("Stephen Rothwell");
2415 MODULE_DESCRIPTION("Advanced Power Management");
2416 MODULE_LICENSE("GPL");
2417 module_param(debug, bool, 0644);
2418 MODULE_PARM_DESC(debug, "Enable debug mode");
2419 module_param(power_off, bool, 0444);
2420 MODULE_PARM_DESC(power_off, "Enable power off");
2421 module_param(bounce_interval, int, 0444);
2422 MODULE_PARM_DESC(bounce_interval,
2423 		"Set the number of ticks to ignore suspend bounces");
2424 module_param(allow_ints, bool, 0444);
2425 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2426 module_param(broken_psr, bool, 0444);
2427 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2428 module_param(realmode_power_off, bool, 0444);
2429 MODULE_PARM_DESC(realmode_power_off,
2430 		"Switch to real mode before powering off");
2431 module_param(idle_threshold, int, 0444);
2432 MODULE_PARM_DESC(idle_threshold,
2433 	"System idle percentage above which to make APM BIOS idle calls");
2434 module_param(idle_period, int, 0444);
2435 MODULE_PARM_DESC(idle_period,
2436 	"Period (in sec/100) over which to calculate the idle percentage");
2437 module_param(smp, bool, 0444);
2438 MODULE_PARM_DESC(smp,
2439 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2440 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2441