xref: /linux/arch/x86/kernel/apm_32.c (revision 6e7fd890f1d6ac83805409e9c346240de2705584)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*-
3  * APM BIOS driver for Linux
4  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
5  *
6  * Initial development of this driver was funded by NEC Australia P/L
7  *	and NEC Corporation
8  *
9  * October 1995, Rik Faith (faith@cs.unc.edu):
10  *    Minor enhancements and updates (to the patch set) for 1.3.x
11  *    Documentation
12  * January 1996, Rik Faith (faith@cs.unc.edu):
13  *    Make /proc/apm easy to format (bump driver version)
14  * March 1996, Rik Faith (faith@cs.unc.edu):
15  *    Prohibit APM BIOS calls unless apm_enabled.
16  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
17  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
18  *    Version 1.0 and 1.1
19  * May 1996, Version 1.2
20  * Feb 1998, Version 1.3
21  * Feb 1998, Version 1.4
22  * Aug 1998, Version 1.5
23  * Sep 1998, Version 1.6
24  * Nov 1998, Version 1.7
25  * Jan 1999, Version 1.8
26  * Jan 1999, Version 1.9
27  * Oct 1999, Version 1.10
28  * Nov 1999, Version 1.11
29  * Jan 2000, Version 1.12
30  * Feb 2000, Version 1.13
31  * Nov 2000, Version 1.14
32  * Oct 2001, Version 1.15
33  * Jan 2002, Version 1.16
34  * Oct 2002, Version 1.16ac
35  *
36  * History:
37  *    0.6b: first version in official kernel, Linux 1.3.46
38  *    0.7: changed /proc/apm format, Linux 1.3.58
39  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
40  *    0.9: only call bios if bios is present, Linux 1.3.72
41  *    1.0: use fixed device number, consolidate /proc/apm into this file,
42  *         Linux 1.3.85
43  *    1.1: support user-space standby and suspend, power off after system
44  *         halted, Linux 1.3.98
45  *    1.2: When resetting RTC after resume, take care so that the time
46  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
47  *         <jtoth@princeton.edu>); improve interaction between
48  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
49  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
50  *	   levels to the printk calls. APM is not defined for SMP machines.
51  *         The new replacement for it is, but Linux doesn't yet support this.
52  *         Alan Cox Linux 2.1.55
53  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
54  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
55  *         Dean Gaudet <dgaudet@arctic.org>.
56  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
57  *    1.5: Fix segment register reloading (in case of bad segments saved
58  *         across BIOS call).
59  *         Stephen Rothwell
60  *    1.6: Cope with compiler/assembler differences.
61  *         Only try to turn off the first display device.
62  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
63  *                   <echter@informatik.uni-rostock.de>
64  *         Stephen Rothwell
65  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
66  *         to reflect current state of APM BIOS.
67  *         Chris Rankin <rankinc@bellsouth.net>
68  *         Reset interrupt 0 timer to 100Hz after suspend
69  *         Chad Miller <cmiller@surfsouth.com>
70  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
71  *         Richard Gooch <rgooch@atnf.csiro.au>
72  *         Allow boot time disabling of APM
73  *         Make boot messages far less verbose by default
74  *         Make asm safer
75  *         Stephen Rothwell
76  *    1.8: Add CONFIG_APM_RTC_IS_GMT
77  *         Richard Gooch <rgooch@atnf.csiro.au>
78  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
79  *         remove dependency on CONFIG_PROC_FS
80  *         Stephen Rothwell
81  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
82  *         Try to cope with BIOS's that need to have all display
83  *         devices blanked and not just the first one.
84  *         Ross Paterson <ross@soi.city.ac.uk>
85  *         Fix segment limit setting it has always been wrong as
86  *         the segments needed to have byte granularity.
87  *         Mark a few things __init.
88  *         Add hack to allow power off of SMP systems by popular request.
89  *         Use CONFIG_SMP instead of __SMP__
90  *         Ignore BOUNCES for three seconds.
91  *         Stephen Rothwell
92  *   1.10: Fix for Thinkpad return code.
93  *         Merge 2.2 and 2.3 drivers.
94  *         Remove APM dependencies in arch/i386/kernel/process.c
95  *         Remove APM dependencies in drivers/char/sysrq.c
96  *         Reset time across standby.
97  *         Allow more initialisation on SMP.
98  *         Remove CONFIG_APM_POWER_OFF and make it boot time
99  *         configurable (default on).
100  *         Make debug only a boot time parameter (remove APM_DEBUG).
101  *         Try to blank all devices on any error.
102  *   1.11: Remove APM dependencies in drivers/char/console.c
103  *         Check nr_running to detect if we are idle (from
104  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
105  *         Fix for bioses that don't zero the top part of the
106  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
107  *         (reported by Panos Katsaloulis <teras@writeme.com>).
108  *         Real mode power off patch (Walter Hofmann
109  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
110  *   1.12: Remove CONFIG_SMP as the compiler will optimize
111  *         the code away anyway (smp_num_cpus == 1 in UP)
112  *         noted by Artur Skawina <skawina@geocities.com>.
113  *         Make power off under SMP work again.
114  *         Fix thinko with initial engaging of BIOS.
115  *         Make sure power off only happens on CPU 0
116  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
117  *         Do error notification to user mode if BIOS calls fail.
118  *         Move entrypoint offset fix to ...boot/setup.S
119  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
120  *         Remove smp-power-off. SMP users must now specify
121  *         "apm=power-off" on the kernel command line. Suggested
122  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
123  *         <alan@lxorguk.ukuu.org.uk>.
124  *         Register the /proc/apm entry even on SMP so that
125  *         scripts that check for it before doing power off
126  *         work (Jim Avera <jima@hal.com>).
127  *   1.13: Changes for new pm_ interfaces (Andy Henroid
128  *         <andy_henroid@yahoo.com>).
129  *         Modularize the code.
130  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
131  *         is now the way life works).
132  *         Fix thinko in suspend() (wrong return).
133  *         Notify drivers on critical suspend.
134  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
135  *         modified by sfr).
136  *         Disable interrupts while we are suspended (Andy Henroid
137  *         <andy_henroid@yahoo.com> fixed by sfr).
138  *         Make power off work on SMP again (Tony Hoyle
139  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
140  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
141  *         interval is now configurable.
142  *   1.14: Make connection version persist across module unload/load.
143  *         Enable and engage power management earlier.
144  *         Disengage power management on module unload.
145  *         Changed to use the sysrq-register hack for registering the
146  *         power off function called by magic sysrq based upon discussions
147  *         in irc://irc.openprojects.net/#kernelnewbies
148  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
149  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
150  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
151  *         Work around byte swap bug in one of the Vaio's BIOS's
152  *         (Marc Boucher <marc@mbsi.ca>).
153  *         Exposed the disable flag to dmi so that we can handle known
154  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
155  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
156  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
157  *         If an APM idle fails log it and idle sensibly
158  *   1.15: Don't queue events to clients who open the device O_WRONLY.
159  *         Don't expect replies from clients who open the device O_RDONLY.
160  *         (Idea from Thomas Hood)
161  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
162  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
163  *         Notify listeners of standby or suspend events before notifying
164  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
165  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
166  *         Ignore first resume after we generate our own resume event
167  *         after a suspend (Thomas Hood)
168  *         Daemonize now gets rid of our controlling terminal (sfr).
169  *         CONFIG_APM_CPU_IDLE now just affects the default value of
170  *         idle_threshold (sfr).
171  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
172  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
173  *	   make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
174  *	   TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
175  *
176  * APM 1.1 Reference:
177  *
178  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
179  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
180  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
181  *
182  * [This document is available free from Intel by calling 800.628.8686 (fax
183  * 916.356.6100) or 800.548.4725; or from
184  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
185  * available from Microsoft by calling 206.882.8080.]
186  *
187  * APM 1.2 Reference:
188  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
189  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
190  *
191  * [This document is available from Microsoft at:
192  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
193  */
194 
195 #define pr_fmt(fmt) "apm: " fmt
196 
197 #include <linux/module.h>
198 
199 #include <linux/poll.h>
200 #include <linux/types.h>
201 #include <linux/stddef.h>
202 #include <linux/timer.h>
203 #include <linux/fcntl.h>
204 #include <linux/slab.h>
205 #include <linux/stat.h>
206 #include <linux/proc_fs.h>
207 #include <linux/seq_file.h>
208 #include <linux/miscdevice.h>
209 #include <linux/apm_bios.h>
210 #include <linux/init.h>
211 #include <linux/time.h>
212 #include <linux/sched/signal.h>
213 #include <linux/sched/cputime.h>
214 #include <linux/pm.h>
215 #include <linux/capability.h>
216 #include <linux/device.h>
217 #include <linux/kernel.h>
218 #include <linux/freezer.h>
219 #include <linux/smp.h>
220 #include <linux/dmi.h>
221 #include <linux/suspend.h>
222 #include <linux/kthread.h>
223 #include <linux/jiffies.h>
224 #include <linux/acpi.h>
225 #include <linux/syscore_ops.h>
226 #include <linux/i8253.h>
227 #include <linux/cpuidle.h>
228 
229 #include <linux/uaccess.h>
230 #include <asm/desc.h>
231 #include <asm/olpc.h>
232 #include <asm/paravirt.h>
233 #include <asm/reboot.h>
234 #include <asm/nospec-branch.h>
235 #include <asm/ibt.h>
236 
237 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
238 extern int (*console_blank_hook)(int);
239 #endif
240 
241 /*
242  * Various options can be changed at boot time as follows:
243  * (We allow underscores for compatibility with the modules code)
244  *	apm=on/off			enable/disable APM
245  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
246  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
247  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
248  *	    					powering off
249  *	    [no-]debug			log some debugging messages
250  *	    [no-]power[-_]off		power off on shutdown
251  *	    [no-]smp			Use apm even on an SMP box
252  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
253  *	    				bounces
254  *          idle[-_]threshold=<n>       System idle percentage above which to
255  *                                      make APM BIOS idle calls. Set it to
256  *                                      100 to disable.
257  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
258  *                                      which the idle percentage is
259  *                                      calculated.
260  */
261 
262 /* KNOWN PROBLEM MACHINES:
263  *
264  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
265  *                         [Confirmed by TI representative]
266  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
267  *                    [Confirmed by BIOS disassembly]
268  *                    [This may work now ...]
269  * P: Toshiba 1950S: battery life information only gets updated after resume
270  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
271  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
272  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
273  * 	Neale Banks <neale@lowendale.com.au> December 2000
274  *
275  * Legend: U = unusable with APM patches
276  *         P = partially usable with APM patches
277  */
278 
279 /*
280  * Define as 1 to make the driver always call the APM BIOS busy
281  * routine even if the clock was not reported as slowed by the
282  * idle routine.  Otherwise, define as 0.
283  */
284 #define ALWAYS_CALL_BUSY   1
285 
286 /*
287  * Define to make the APM BIOS calls zero all data segment registers (so
288  * that an incorrect BIOS implementation will cause a kernel panic if it
289  * tries to write to arbitrary memory).
290  */
291 #define APM_ZERO_SEGS
292 
293 #include <asm/apm.h>
294 
295 /*
296  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
297  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
298  * David Chen <chen@ctpa04.mit.edu>
299  */
300 #undef INIT_TIMER_AFTER_SUSPEND
301 
302 #ifdef INIT_TIMER_AFTER_SUSPEND
303 #include <linux/timex.h>
304 #include <asm/io.h>
305 #include <linux/delay.h>
306 #endif
307 
308 /*
309  * Need to poll the APM BIOS every second
310  */
311 #define APM_CHECK_TIMEOUT	(HZ)
312 
313 /*
314  * Ignore suspend events for this amount of time after a resume
315  */
316 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
317 
318 /*
319  * Maximum number of events stored
320  */
321 #define APM_MAX_EVENTS		20
322 
323 /*
324  * The per-file APM data
325  */
326 struct apm_user {
327 	int		magic;
328 	struct apm_user *next;
329 	unsigned int	suser: 1;
330 	unsigned int	writer: 1;
331 	unsigned int	reader: 1;
332 	unsigned int	suspend_wait: 1;
333 	int		suspend_result;
334 	int		suspends_pending;
335 	int		standbys_pending;
336 	int		suspends_read;
337 	int		standbys_read;
338 	int		event_head;
339 	int		event_tail;
340 	apm_event_t	events[APM_MAX_EVENTS];
341 };
342 
343 /*
344  * The magic number in apm_user
345  */
346 #define APM_BIOS_MAGIC		0x4101
347 
348 /*
349  * idle percentage above which bios idle calls are done
350  */
351 #ifdef CONFIG_APM_CPU_IDLE
352 #define DEFAULT_IDLE_THRESHOLD	95
353 #else
354 #define DEFAULT_IDLE_THRESHOLD	100
355 #endif
356 #define DEFAULT_IDLE_PERIOD	(100 / 3)
357 
358 static int apm_cpu_idle(struct cpuidle_device *dev,
359 			struct cpuidle_driver *drv, int index);
360 
361 static struct cpuidle_driver apm_idle_driver = {
362 	.name = "apm_idle",
363 	.owner = THIS_MODULE,
364 	.states = {
365 		{ /* entry 0 is for polling */ },
366 		{ /* entry 1 is for APM idle */
367 			.name = "APM",
368 			.desc = "APM idle",
369 			.exit_latency = 250,	/* WAG */
370 			.target_residency = 500,	/* WAG */
371 			.enter = &apm_cpu_idle
372 		},
373 	},
374 	.state_count = 2,
375 };
376 
377 static struct cpuidle_device apm_cpuidle_device;
378 
379 /*
380  * Local variables
381  */
382 __visible struct {
383 	unsigned long	offset;
384 	unsigned short	segment;
385 } apm_bios_entry;
386 static int clock_slowed;
387 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
388 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
389 static int suspends_pending;
390 static int standbys_pending;
391 static int ignore_sys_suspend;
392 static int ignore_normal_resume;
393 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
394 
395 static bool debug __read_mostly;
396 static bool smp __read_mostly;
397 static int apm_disabled = -1;
398 #ifdef CONFIG_SMP
399 static bool power_off;
400 #else
401 static bool power_off = 1;
402 #endif
403 static bool realmode_power_off;
404 #ifdef CONFIG_APM_ALLOW_INTS
405 static bool allow_ints = 1;
406 #else
407 static bool allow_ints;
408 #endif
409 static bool broken_psr;
410 
411 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
412 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
413 static struct apm_user *user_list;
414 static DEFINE_SPINLOCK(user_list_lock);
415 static DEFINE_MUTEX(apm_mutex);
416 
417 /*
418  * Set up a segment that references the real mode segment 0x40
419  * that extends up to the end of page zero (that we have reserved).
420  * This is for buggy BIOS's that refer to (real mode) segment 0x40
421  * even though they are called in protected mode.
422  */
423 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(DESC_DATA32_BIOS,
424 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
425 
426 static const char driver_version[] = "1.16ac";	/* no spaces */
427 
428 static struct task_struct *kapmd_task;
429 
430 /*
431  *	APM event names taken from the APM 1.2 specification. These are
432  *	the message codes that the BIOS uses to tell us about events
433  */
434 static const char * const apm_event_name[] = {
435 	"system standby",
436 	"system suspend",
437 	"normal resume",
438 	"critical resume",
439 	"low battery",
440 	"power status change",
441 	"update time",
442 	"critical suspend",
443 	"user standby",
444 	"user suspend",
445 	"system standby resume",
446 	"capabilities change"
447 };
448 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
449 
450 typedef struct lookup_t {
451 	int	key;
452 	char 	*msg;
453 } lookup_t;
454 
455 /*
456  *	The BIOS returns a set of standard error codes in AX when the
457  *	carry flag is set.
458  */
459 
460 static const lookup_t error_table[] = {
461 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
462 	{ APM_DISABLED,		"Power management disabled" },
463 	{ APM_CONNECTED,	"Real mode interface already connected" },
464 	{ APM_NOT_CONNECTED,	"Interface not connected" },
465 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
466 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
467 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
468 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
469 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
470 	{ APM_BAD_PARAM,	"Parameter out of range" },
471 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
472 	{ APM_BAD_FUNCTION,     "Function not supported" },
473 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
474 	{ APM_BAD_STATE,	"Unable to enter requested state" },
475 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
476 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
477 	{ APM_NOT_PRESENT,	"No APM present" }
478 };
479 #define ERROR_COUNT	ARRAY_SIZE(error_table)
480 
481 /**
482  *	apm_error	-	display an APM error
483  *	@str: information string
484  *	@err: APM BIOS return code
485  *
486  *	Write a meaningful log entry to the kernel log in the event of
487  *	an APM error.  Note that this also handles (negative) kernel errors.
488  */
489 
490 static void apm_error(char *str, int err)
491 {
492 	int i;
493 
494 	for (i = 0; i < ERROR_COUNT; i++)
495 		if (error_table[i].key == err)
496 			break;
497 	if (i < ERROR_COUNT)
498 		pr_notice("%s: %s\n", str, error_table[i].msg);
499 	else if (err < 0)
500 		pr_notice("%s: linux error code %i\n", str, err);
501 	else
502 		pr_notice("%s: unknown error code %#2.2x\n",
503 		       str, err);
504 }
505 
506 /*
507  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
508  * apm_info.allow_ints, we are being really paranoid here!  Not only
509  * are interrupts disabled, but all the segment registers (except SS)
510  * are saved and zeroed this means that if the BIOS tries to reference
511  * any data without explicitly loading the segment registers, the kernel
512  * will fault immediately rather than have some unforeseen circumstances
513  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
514  * this depends on CS referring to the same physical memory as DS so that
515  * DS can be zeroed before the call. Unfortunately, we can't do anything
516  * about the stack segment/pointer.  Also, we tell the compiler that
517  * everything could change.
518  *
519  * Also, we KNOW that for the non error case of apm_bios_call, there
520  * is no useful data returned in the low order 8 bits of eax.
521  */
522 
523 static inline unsigned long __apm_irq_save(void)
524 {
525 	unsigned long flags;
526 	local_save_flags(flags);
527 	if (apm_info.allow_ints) {
528 		if (irqs_disabled_flags(flags))
529 			local_irq_enable();
530 	} else
531 		local_irq_disable();
532 
533 	return flags;
534 }
535 
536 #define apm_irq_save(flags) \
537 	do { flags = __apm_irq_save(); } while (0)
538 
539 static inline void apm_irq_restore(unsigned long flags)
540 {
541 	if (irqs_disabled_flags(flags))
542 		local_irq_disable();
543 	else if (irqs_disabled())
544 		local_irq_enable();
545 }
546 
547 #ifdef APM_ZERO_SEGS
548 #	define APM_DECL_SEGS \
549 		unsigned int saved_fs; unsigned int saved_gs;
550 #	define APM_DO_SAVE_SEGS \
551 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
552 #	define APM_DO_RESTORE_SEGS \
553 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
554 #else
555 #	define APM_DECL_SEGS
556 #	define APM_DO_SAVE_SEGS
557 #	define APM_DO_RESTORE_SEGS
558 #endif
559 
560 struct apm_bios_call {
561 	u32 func;
562 	/* In and out */
563 	u32 ebx;
564 	u32 ecx;
565 	/* Out only */
566 	u32 eax;
567 	u32 edx;
568 	u32 esi;
569 
570 	/* Error: -ENOMEM, or bits 8-15 of eax */
571 	int err;
572 };
573 
574 /**
575  *	__apm_bios_call - Make an APM BIOS 32bit call
576  *	@_call: pointer to struct apm_bios_call.
577  *
578  *	Make an APM call using the 32bit protected mode interface. The
579  *	caller is responsible for knowing if APM BIOS is configured and
580  *	enabled. This call can disable interrupts for a long period of
581  *	time on some laptops.  The return value is in AH and the carry
582  *	flag is loaded into AL.  If there is an error, then the error
583  *	code is returned in AH (bits 8-15 of eax) and this function
584  *	returns non-zero.
585  *
586  *	Note: this makes the call on the current CPU.
587  */
588 static long __apm_bios_call(void *_call)
589 {
590 	APM_DECL_SEGS
591 	unsigned long		flags;
592 	int			cpu;
593 	struct desc_struct	save_desc_40;
594 	struct desc_struct	*gdt;
595 	struct apm_bios_call	*call = _call;
596 	u64			ibt;
597 
598 	cpu = get_cpu();
599 	BUG_ON(cpu != 0);
600 	gdt = get_cpu_gdt_rw(cpu);
601 	save_desc_40 = gdt[0x40 / 8];
602 	gdt[0x40 / 8] = bad_bios_desc;
603 
604 	apm_irq_save(flags);
605 	firmware_restrict_branch_speculation_start();
606 	ibt = ibt_save(true);
607 	APM_DO_SAVE_SEGS;
608 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
609 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
610 			  &call->esi);
611 	APM_DO_RESTORE_SEGS;
612 	ibt_restore(ibt);
613 	firmware_restrict_branch_speculation_end();
614 	apm_irq_restore(flags);
615 	gdt[0x40 / 8] = save_desc_40;
616 	put_cpu();
617 
618 	return call->eax & 0xff;
619 }
620 
621 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
622 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
623 {
624 	int ret;
625 
626 	/* Don't bother with work_on_cpu in the common case, so we don't
627 	 * have to worry about OOM or overhead. */
628 	if (get_cpu() == 0) {
629 		ret = fn(call);
630 		put_cpu();
631 	} else {
632 		put_cpu();
633 		ret = work_on_cpu(0, fn, call);
634 	}
635 
636 	/* work_on_cpu can fail with -ENOMEM */
637 	if (ret < 0)
638 		call->err = ret;
639 	else
640 		call->err = (call->eax >> 8) & 0xff;
641 
642 	return ret;
643 }
644 
645 /**
646  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
647  *	@call: the apm_bios_call registers.
648  *
649  *	If there is an error, it is returned in @call.err.
650  */
651 static int apm_bios_call(struct apm_bios_call *call)
652 {
653 	return on_cpu0(__apm_bios_call, call);
654 }
655 
656 /**
657  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
658  *	@_call: pointer to struct apm_bios_call.
659  *
660  *	Make a BIOS call that returns one value only, or just status.
661  *	If there is an error, then the error code is returned in AH
662  *	(bits 8-15 of eax) and this function returns non-zero (it can
663  *	also return -ENOMEM). This is used for simpler BIOS operations.
664  *	This call may hold interrupts off for a long time on some laptops.
665  *
666  *	Note: this makes the call on the current CPU.
667  */
668 static long __apm_bios_call_simple(void *_call)
669 {
670 	u8			error;
671 	APM_DECL_SEGS
672 	unsigned long		flags;
673 	int			cpu;
674 	struct desc_struct	save_desc_40;
675 	struct desc_struct	*gdt;
676 	struct apm_bios_call	*call = _call;
677 	u64			ibt;
678 
679 	cpu = get_cpu();
680 	BUG_ON(cpu != 0);
681 	gdt = get_cpu_gdt_rw(cpu);
682 	save_desc_40 = gdt[0x40 / 8];
683 	gdt[0x40 / 8] = bad_bios_desc;
684 
685 	apm_irq_save(flags);
686 	firmware_restrict_branch_speculation_start();
687 	ibt = ibt_save(true);
688 	APM_DO_SAVE_SEGS;
689 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
690 					 &call->eax);
691 	APM_DO_RESTORE_SEGS;
692 	ibt_restore(ibt);
693 	firmware_restrict_branch_speculation_end();
694 	apm_irq_restore(flags);
695 	gdt[0x40 / 8] = save_desc_40;
696 	put_cpu();
697 	return error;
698 }
699 
700 /**
701  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
702  *	@func: APM function to invoke
703  *	@ebx_in: EBX register value for BIOS call
704  *	@ecx_in: ECX register value for BIOS call
705  *	@eax: EAX register on return from the BIOS call
706  *	@err: bits
707  *
708  *	Make a BIOS call that returns one value only, or just status.
709  *	If there is an error, then the error code is returned in @err
710  *	and this function returns non-zero. This is used for simpler
711  *	BIOS operations.  This call may hold interrupts off for a long
712  *	time on some laptops.
713  */
714 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
715 				int *err)
716 {
717 	struct apm_bios_call call;
718 	int ret;
719 
720 	call.func = func;
721 	call.ebx = ebx_in;
722 	call.ecx = ecx_in;
723 
724 	ret = on_cpu0(__apm_bios_call_simple, &call);
725 	*eax = call.eax;
726 	*err = call.err;
727 	return ret;
728 }
729 
730 /**
731  *	apm_driver_version	-	APM driver version
732  *	@val:	loaded with the APM version on return
733  *
734  *	Retrieve the APM version supported by the BIOS. This is only
735  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
736  *	probably present.
737  *
738  *	On entry val should point to a value indicating the APM driver
739  *	version with the high byte being the major and the low byte the
740  *	minor number both in BCD
741  *
742  *	On return it will hold the BIOS revision supported in the
743  *	same format.
744  */
745 
746 static int apm_driver_version(u_short *val)
747 {
748 	u32 eax;
749 	int err;
750 
751 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
752 		return err;
753 	*val = eax;
754 	return APM_SUCCESS;
755 }
756 
757 /**
758  *	apm_get_event	-	get an APM event from the BIOS
759  *	@event: pointer to the event
760  *	@info: point to the event information
761  *
762  *	The APM BIOS provides a polled information for event
763  *	reporting. The BIOS expects to be polled at least every second
764  *	when events are pending. When a message is found the caller should
765  *	poll until no more messages are present.  However, this causes
766  *	problems on some laptops where a suspend event notification is
767  *	not cleared until it is acknowledged.
768  *
769  *	Additional information is returned in the info pointer, providing
770  *	that APM 1.2 is in use. If no messages are pending the value 0x80
771  *	is returned (No power management events pending).
772  */
773 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
774 {
775 	struct apm_bios_call call;
776 
777 	call.func = APM_FUNC_GET_EVENT;
778 	call.ebx = call.ecx = 0;
779 
780 	if (apm_bios_call(&call))
781 		return call.err;
782 
783 	*event = call.ebx;
784 	if (apm_info.connection_version < 0x0102)
785 		*info = ~0; /* indicate info not valid */
786 	else
787 		*info = call.ecx;
788 	return APM_SUCCESS;
789 }
790 
791 /**
792  *	set_power_state	-	set the power management state
793  *	@what: which items to transition
794  *	@state: state to transition to
795  *
796  *	Request an APM change of state for one or more system devices. The
797  *	processor state must be transitioned last of all. what holds the
798  *	class of device in the upper byte and the device number (0xFF for
799  *	all) for the object to be transitioned.
800  *
801  *	The state holds the state to transition to, which may in fact
802  *	be an acceptance of a BIOS requested state change.
803  */
804 
805 static int set_power_state(u_short what, u_short state)
806 {
807 	u32 eax;
808 	int err;
809 
810 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
811 		return err;
812 	return APM_SUCCESS;
813 }
814 
815 /**
816  *	set_system_power_state - set system wide power state
817  *	@state: which state to enter
818  *
819  *	Transition the entire system into a new APM power state.
820  */
821 
822 static int set_system_power_state(u_short state)
823 {
824 	return set_power_state(APM_DEVICE_ALL, state);
825 }
826 
827 /**
828  *	apm_do_idle	-	perform power saving
829  *
830  *	This function notifies the BIOS that the processor is (in the view
831  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
832  *	to handle the idle request. On a success the function returns 1
833  *	if the BIOS did clock slowing or 0 otherwise.
834  */
835 
836 static int apm_do_idle(void)
837 {
838 	u32 eax;
839 	u8 ret = 0;
840 	int idled = 0;
841 	int err = 0;
842 
843 	if (!need_resched()) {
844 		idled = 1;
845 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
846 	}
847 
848 	if (!idled)
849 		return 0;
850 
851 	if (ret) {
852 		static unsigned long t;
853 
854 		/* This always fails on some SMP boards running UP kernels.
855 		 * Only report the failure the first 5 times.
856 		 */
857 		if (++t < 5) {
858 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
859 			t = jiffies;
860 		}
861 		return -1;
862 	}
863 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
864 	return clock_slowed;
865 }
866 
867 /**
868  *	apm_do_busy	-	inform the BIOS the CPU is busy
869  *
870  *	Request that the BIOS brings the CPU back to full performance.
871  */
872 
873 static void apm_do_busy(void)
874 {
875 	u32 dummy;
876 	int err;
877 
878 	if (clock_slowed || ALWAYS_CALL_BUSY) {
879 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
880 		clock_slowed = 0;
881 	}
882 }
883 
884 /*
885  * If no process has really been interested in
886  * the CPU for some time, we want to call BIOS
887  * power management - we probably want
888  * to conserve power.
889  */
890 #define IDLE_CALC_LIMIT	(HZ * 100)
891 #define IDLE_LEAKY_MAX	16
892 
893 /**
894  * apm_cpu_idle		-	cpu idling for APM capable Linux
895  *
896  * This is the idling function the kernel executes when APM is available. It
897  * tries to do BIOS powermanagement based on the average system idle time.
898  * Furthermore it calls the system default idle routine.
899  */
900 
901 static int apm_cpu_idle(struct cpuidle_device *dev,
902 	struct cpuidle_driver *drv, int index)
903 {
904 	static int use_apm_idle; /* = 0 */
905 	static unsigned int last_jiffies; /* = 0 */
906 	static u64 last_stime; /* = 0 */
907 	u64 stime, utime;
908 
909 	int apm_idle_done = 0;
910 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
911 	unsigned int bucket;
912 
913 recalc:
914 	task_cputime(current, &utime, &stime);
915 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
916 		use_apm_idle = 0;
917 	} else if (jiffies_since_last_check > idle_period) {
918 		unsigned int idle_percentage;
919 
920 		idle_percentage = nsecs_to_jiffies(stime - last_stime);
921 		idle_percentage *= 100;
922 		idle_percentage /= jiffies_since_last_check;
923 		use_apm_idle = (idle_percentage > idle_threshold);
924 		if (apm_info.forbid_idle)
925 			use_apm_idle = 0;
926 	}
927 
928 	last_jiffies = jiffies;
929 	last_stime = stime;
930 
931 	bucket = IDLE_LEAKY_MAX;
932 
933 	while (!need_resched()) {
934 		if (use_apm_idle) {
935 			unsigned int t;
936 
937 			t = jiffies;
938 			switch (apm_do_idle()) {
939 			case 0:
940 				apm_idle_done = 1;
941 				if (t != jiffies) {
942 					if (bucket) {
943 						bucket = IDLE_LEAKY_MAX;
944 						continue;
945 					}
946 				} else if (bucket) {
947 					bucket--;
948 					continue;
949 				}
950 				break;
951 			case 1:
952 				apm_idle_done = 1;
953 				break;
954 			default: /* BIOS refused */
955 				break;
956 			}
957 		}
958 		default_idle();
959 		local_irq_disable();
960 		jiffies_since_last_check = jiffies - last_jiffies;
961 		if (jiffies_since_last_check > idle_period)
962 			goto recalc;
963 	}
964 
965 	if (apm_idle_done)
966 		apm_do_busy();
967 
968 	return index;
969 }
970 
971 /**
972  *	apm_power_off	-	ask the BIOS to power off
973  *
974  *	Handle the power off sequence. This is the one piece of code we
975  *	will execute even on SMP machines. In order to deal with BIOS
976  *	bugs we support real mode APM BIOS power off calls. We also make
977  *	the SMP call on CPU0 as some systems will only honour this call
978  *	on their first cpu.
979  */
980 
981 static void apm_power_off(void)
982 {
983 	/* Some bioses don't like being called from CPU != 0 */
984 	if (apm_info.realmode_power_off) {
985 		set_cpus_allowed_ptr(current, cpumask_of(0));
986 		machine_real_restart(MRR_APM);
987 	} else {
988 		(void)set_system_power_state(APM_STATE_OFF);
989 	}
990 }
991 
992 #ifdef CONFIG_APM_DO_ENABLE
993 
994 /**
995  *	apm_enable_power_management - enable BIOS APM power management
996  *	@enable: enable yes/no
997  *
998  *	Enable or disable the APM BIOS power services.
999  */
1000 
1001 static int apm_enable_power_management(int enable)
1002 {
1003 	u32 eax;
1004 	int err;
1005 
1006 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1007 		return APM_NOT_ENGAGED;
1008 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1009 				 enable, &eax, &err))
1010 		return err;
1011 	if (enable)
1012 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1013 	else
1014 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1015 	return APM_SUCCESS;
1016 }
1017 #endif
1018 
1019 /**
1020  *	apm_get_power_status	-	get current power state
1021  *	@status: returned status
1022  *	@bat: battery info
1023  *	@life: estimated life
1024  *
1025  *	Obtain the current power status from the APM BIOS. We return a
1026  *	status which gives the rough battery status, and current power
1027  *	source. The bat value returned give an estimate as a percentage
1028  *	of life and a status value for the battery. The estimated life
1029  *	if reported is a lifetime in seconds/minutes at current power
1030  *	consumption.
1031  */
1032 
1033 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1034 {
1035 	struct apm_bios_call call;
1036 
1037 	call.func = APM_FUNC_GET_STATUS;
1038 	call.ebx = APM_DEVICE_ALL;
1039 	call.ecx = 0;
1040 
1041 	if (apm_info.get_power_status_broken)
1042 		return APM_32_UNSUPPORTED;
1043 	if (apm_bios_call(&call)) {
1044 		if (!call.err)
1045 			return APM_NO_ERROR;
1046 		return call.err;
1047 	}
1048 	*status = call.ebx;
1049 	*bat = call.ecx;
1050 	if (apm_info.get_power_status_swabinminutes) {
1051 		*life = swab16((u16)call.edx);
1052 		*life |= 0x8000;
1053 	} else
1054 		*life = call.edx;
1055 	return APM_SUCCESS;
1056 }
1057 
1058 /**
1059  *	apm_engage_power_management	-	enable PM on a device
1060  *	@device: identity of device
1061  *	@enable: on/off
1062  *
1063  *	Activate or deactivate power management on either a specific device
1064  *	or the entire system (%APM_DEVICE_ALL).
1065  */
1066 
1067 static int apm_engage_power_management(u_short device, int enable)
1068 {
1069 	u32 eax;
1070 	int err;
1071 
1072 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1073 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1074 		return APM_DISABLED;
1075 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1076 				 &eax, &err))
1077 		return err;
1078 	if (device == APM_DEVICE_ALL) {
1079 		if (enable)
1080 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1081 		else
1082 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1083 	}
1084 	return APM_SUCCESS;
1085 }
1086 
1087 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1088 
1089 /**
1090  *	apm_console_blank	-	blank the display
1091  *	@blank: on/off
1092  *
1093  *	Attempt to blank the console, firstly by blanking just video device
1094  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1095  *	all video devices. Typically the BIOS will do laptop backlight and
1096  *	monitor powerdown for us.
1097  */
1098 
1099 static int apm_console_blank(int blank)
1100 {
1101 	int error = APM_NOT_ENGAGED; /* silence gcc */
1102 	int i;
1103 	u_short state;
1104 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1105 
1106 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1107 
1108 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1109 		error = set_power_state(dev[i], state);
1110 
1111 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1112 			return 1;
1113 
1114 		if (error == APM_NOT_ENGAGED)
1115 			break;
1116 	}
1117 
1118 	if (error == APM_NOT_ENGAGED) {
1119 		static int tried;
1120 		int eng_error;
1121 		if (tried++ == 0) {
1122 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1123 			if (eng_error) {
1124 				apm_error("set display", error);
1125 				apm_error("engage interface", eng_error);
1126 				return 0;
1127 			} else
1128 				return apm_console_blank(blank);
1129 		}
1130 	}
1131 	apm_error("set display", error);
1132 	return 0;
1133 }
1134 #endif
1135 
1136 static int queue_empty(struct apm_user *as)
1137 {
1138 	return as->event_head == as->event_tail;
1139 }
1140 
1141 static apm_event_t get_queued_event(struct apm_user *as)
1142 {
1143 	if (++as->event_tail >= APM_MAX_EVENTS)
1144 		as->event_tail = 0;
1145 	return as->events[as->event_tail];
1146 }
1147 
1148 static void queue_event(apm_event_t event, struct apm_user *sender)
1149 {
1150 	struct apm_user *as;
1151 
1152 	spin_lock(&user_list_lock);
1153 	if (user_list == NULL)
1154 		goto out;
1155 	for (as = user_list; as != NULL; as = as->next) {
1156 		if ((as == sender) || (!as->reader))
1157 			continue;
1158 		if (++as->event_head >= APM_MAX_EVENTS)
1159 			as->event_head = 0;
1160 
1161 		if (as->event_head == as->event_tail) {
1162 			static int notified;
1163 
1164 			if (notified++ == 0)
1165 				pr_err("an event queue overflowed\n");
1166 			if (++as->event_tail >= APM_MAX_EVENTS)
1167 				as->event_tail = 0;
1168 		}
1169 		as->events[as->event_head] = event;
1170 		if (!as->suser || !as->writer)
1171 			continue;
1172 		switch (event) {
1173 		case APM_SYS_SUSPEND:
1174 		case APM_USER_SUSPEND:
1175 			as->suspends_pending++;
1176 			suspends_pending++;
1177 			break;
1178 
1179 		case APM_SYS_STANDBY:
1180 		case APM_USER_STANDBY:
1181 			as->standbys_pending++;
1182 			standbys_pending++;
1183 			break;
1184 		}
1185 	}
1186 	wake_up_interruptible(&apm_waitqueue);
1187 out:
1188 	spin_unlock(&user_list_lock);
1189 }
1190 
1191 static void reinit_timer(void)
1192 {
1193 #ifdef INIT_TIMER_AFTER_SUSPEND
1194 	unsigned long flags;
1195 
1196 	raw_spin_lock_irqsave(&i8253_lock, flags);
1197 	/* set the clock to HZ */
1198 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1199 	udelay(10);
1200 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1201 	udelay(10);
1202 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1203 	udelay(10);
1204 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1205 #endif
1206 }
1207 
1208 static int suspend(int vetoable)
1209 {
1210 	int err;
1211 	struct apm_user	*as;
1212 
1213 	dpm_suspend_start(PMSG_SUSPEND);
1214 	dpm_suspend_end(PMSG_SUSPEND);
1215 
1216 	local_irq_disable();
1217 	syscore_suspend();
1218 
1219 	local_irq_enable();
1220 
1221 	save_processor_state();
1222 	err = set_system_power_state(APM_STATE_SUSPEND);
1223 	ignore_normal_resume = 1;
1224 	restore_processor_state();
1225 
1226 	local_irq_disable();
1227 	reinit_timer();
1228 
1229 	if (err == APM_NO_ERROR)
1230 		err = APM_SUCCESS;
1231 	if (err != APM_SUCCESS)
1232 		apm_error("suspend", err);
1233 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1234 
1235 	syscore_resume();
1236 	local_irq_enable();
1237 
1238 	dpm_resume_start(PMSG_RESUME);
1239 	dpm_resume_end(PMSG_RESUME);
1240 
1241 	queue_event(APM_NORMAL_RESUME, NULL);
1242 	spin_lock(&user_list_lock);
1243 	for (as = user_list; as != NULL; as = as->next) {
1244 		as->suspend_wait = 0;
1245 		as->suspend_result = err;
1246 	}
1247 	spin_unlock(&user_list_lock);
1248 	wake_up_interruptible(&apm_suspend_waitqueue);
1249 	return err;
1250 }
1251 
1252 static void standby(void)
1253 {
1254 	int err;
1255 
1256 	dpm_suspend_end(PMSG_SUSPEND);
1257 
1258 	local_irq_disable();
1259 	syscore_suspend();
1260 	local_irq_enable();
1261 
1262 	err = set_system_power_state(APM_STATE_STANDBY);
1263 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1264 		apm_error("standby", err);
1265 
1266 	local_irq_disable();
1267 	syscore_resume();
1268 	local_irq_enable();
1269 
1270 	dpm_resume_start(PMSG_RESUME);
1271 }
1272 
1273 static apm_event_t get_event(void)
1274 {
1275 	int error;
1276 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1277 	apm_eventinfo_t	info;
1278 
1279 	static int notified;
1280 
1281 	/* we don't use the eventinfo */
1282 	error = apm_get_event(&event, &info);
1283 	if (error == APM_SUCCESS)
1284 		return event;
1285 
1286 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1287 		apm_error("get_event", error);
1288 
1289 	return 0;
1290 }
1291 
1292 static void check_events(void)
1293 {
1294 	apm_event_t event;
1295 	static unsigned long last_resume;
1296 	static int ignore_bounce;
1297 
1298 	while ((event = get_event()) != 0) {
1299 		if (debug) {
1300 			if (event <= NR_APM_EVENT_NAME)
1301 				printk(KERN_DEBUG "apm: received %s notify\n",
1302 				       apm_event_name[event - 1]);
1303 			else
1304 				printk(KERN_DEBUG "apm: received unknown "
1305 				       "event 0x%02x\n", event);
1306 		}
1307 		if (ignore_bounce
1308 		    && (time_after(jiffies, last_resume + bounce_interval)))
1309 			ignore_bounce = 0;
1310 
1311 		switch (event) {
1312 		case APM_SYS_STANDBY:
1313 		case APM_USER_STANDBY:
1314 			queue_event(event, NULL);
1315 			if (standbys_pending <= 0)
1316 				standby();
1317 			break;
1318 
1319 		case APM_USER_SUSPEND:
1320 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1321 			if (apm_info.connection_version > 0x100)
1322 				set_system_power_state(APM_STATE_REJECT);
1323 			break;
1324 #endif
1325 		case APM_SYS_SUSPEND:
1326 			if (ignore_bounce) {
1327 				if (apm_info.connection_version > 0x100)
1328 					set_system_power_state(APM_STATE_REJECT);
1329 				break;
1330 			}
1331 			/*
1332 			 * If we are already processing a SUSPEND,
1333 			 * then further SUSPEND events from the BIOS
1334 			 * will be ignored.  We also return here to
1335 			 * cope with the fact that the Thinkpads keep
1336 			 * sending a SUSPEND event until something else
1337 			 * happens!
1338 			 */
1339 			if (ignore_sys_suspend)
1340 				return;
1341 			ignore_sys_suspend = 1;
1342 			queue_event(event, NULL);
1343 			if (suspends_pending <= 0)
1344 				(void) suspend(1);
1345 			break;
1346 
1347 		case APM_NORMAL_RESUME:
1348 		case APM_CRITICAL_RESUME:
1349 		case APM_STANDBY_RESUME:
1350 			ignore_sys_suspend = 0;
1351 			last_resume = jiffies;
1352 			ignore_bounce = 1;
1353 			if ((event != APM_NORMAL_RESUME)
1354 			    || (ignore_normal_resume == 0)) {
1355 				dpm_resume_end(PMSG_RESUME);
1356 				queue_event(event, NULL);
1357 			}
1358 			ignore_normal_resume = 0;
1359 			break;
1360 
1361 		case APM_CAPABILITY_CHANGE:
1362 		case APM_LOW_BATTERY:
1363 		case APM_POWER_STATUS_CHANGE:
1364 			queue_event(event, NULL);
1365 			/* If needed, notify drivers here */
1366 			break;
1367 
1368 		case APM_UPDATE_TIME:
1369 			break;
1370 
1371 		case APM_CRITICAL_SUSPEND:
1372 			/*
1373 			 * We are not allowed to reject a critical suspend.
1374 			 */
1375 			(void)suspend(0);
1376 			break;
1377 		}
1378 	}
1379 }
1380 
1381 static void apm_event_handler(void)
1382 {
1383 	static int pending_count = 4;
1384 	int err;
1385 
1386 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1387 		if ((apm_info.connection_version > 0x100) &&
1388 		    (pending_count-- <= 0)) {
1389 			pending_count = 4;
1390 			if (debug)
1391 				printk(KERN_DEBUG "apm: setting state busy\n");
1392 			err = set_system_power_state(APM_STATE_BUSY);
1393 			if (err)
1394 				apm_error("busy", err);
1395 		}
1396 	} else
1397 		pending_count = 4;
1398 	check_events();
1399 }
1400 
1401 /*
1402  * This is the APM thread main loop.
1403  */
1404 
1405 static void apm_mainloop(void)
1406 {
1407 	DECLARE_WAITQUEUE(wait, current);
1408 
1409 	add_wait_queue(&apm_waitqueue, &wait);
1410 	set_current_state(TASK_INTERRUPTIBLE);
1411 	for (;;) {
1412 		schedule_timeout(APM_CHECK_TIMEOUT);
1413 		if (kthread_should_stop())
1414 			break;
1415 		/*
1416 		 * Ok, check all events, check for idle (and mark us sleeping
1417 		 * so as not to count towards the load average)..
1418 		 */
1419 		set_current_state(TASK_INTERRUPTIBLE);
1420 		apm_event_handler();
1421 	}
1422 	remove_wait_queue(&apm_waitqueue, &wait);
1423 }
1424 
1425 static int check_apm_user(struct apm_user *as, const char *func)
1426 {
1427 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1428 		pr_err("%s passed bad filp\n", func);
1429 		return 1;
1430 	}
1431 	return 0;
1432 }
1433 
1434 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1435 {
1436 	struct apm_user *as;
1437 	int i;
1438 	apm_event_t event;
1439 
1440 	as = fp->private_data;
1441 	if (check_apm_user(as, "read"))
1442 		return -EIO;
1443 	if ((int)count < sizeof(apm_event_t))
1444 		return -EINVAL;
1445 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1446 		return -EAGAIN;
1447 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1448 	i = count;
1449 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1450 		event = get_queued_event(as);
1451 		if (copy_to_user(buf, &event, sizeof(event))) {
1452 			if (i < count)
1453 				break;
1454 			return -EFAULT;
1455 		}
1456 		switch (event) {
1457 		case APM_SYS_SUSPEND:
1458 		case APM_USER_SUSPEND:
1459 			as->suspends_read++;
1460 			break;
1461 
1462 		case APM_SYS_STANDBY:
1463 		case APM_USER_STANDBY:
1464 			as->standbys_read++;
1465 			break;
1466 		}
1467 		buf += sizeof(event);
1468 		i -= sizeof(event);
1469 	}
1470 	if (i < count)
1471 		return count - i;
1472 	if (signal_pending(current))
1473 		return -ERESTARTSYS;
1474 	return 0;
1475 }
1476 
1477 static __poll_t do_poll(struct file *fp, poll_table *wait)
1478 {
1479 	struct apm_user *as;
1480 
1481 	as = fp->private_data;
1482 	if (check_apm_user(as, "poll"))
1483 		return 0;
1484 	poll_wait(fp, &apm_waitqueue, wait);
1485 	if (!queue_empty(as))
1486 		return EPOLLIN | EPOLLRDNORM;
1487 	return 0;
1488 }
1489 
1490 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1491 {
1492 	struct apm_user *as;
1493 	int ret;
1494 
1495 	as = filp->private_data;
1496 	if (check_apm_user(as, "ioctl"))
1497 		return -EIO;
1498 	if (!as->suser || !as->writer)
1499 		return -EPERM;
1500 	switch (cmd) {
1501 	case APM_IOC_STANDBY:
1502 		mutex_lock(&apm_mutex);
1503 		if (as->standbys_read > 0) {
1504 			as->standbys_read--;
1505 			as->standbys_pending--;
1506 			standbys_pending--;
1507 		} else
1508 			queue_event(APM_USER_STANDBY, as);
1509 		if (standbys_pending <= 0)
1510 			standby();
1511 		mutex_unlock(&apm_mutex);
1512 		break;
1513 	case APM_IOC_SUSPEND:
1514 		mutex_lock(&apm_mutex);
1515 		if (as->suspends_read > 0) {
1516 			as->suspends_read--;
1517 			as->suspends_pending--;
1518 			suspends_pending--;
1519 		} else
1520 			queue_event(APM_USER_SUSPEND, as);
1521 		if (suspends_pending <= 0) {
1522 			ret = suspend(1);
1523 			mutex_unlock(&apm_mutex);
1524 		} else {
1525 			as->suspend_wait = 1;
1526 			mutex_unlock(&apm_mutex);
1527 			wait_event_interruptible(apm_suspend_waitqueue,
1528 					as->suspend_wait == 0);
1529 			ret = as->suspend_result;
1530 		}
1531 		return ret;
1532 	default:
1533 		return -ENOTTY;
1534 	}
1535 	return 0;
1536 }
1537 
1538 static int do_release(struct inode *inode, struct file *filp)
1539 {
1540 	struct apm_user *as;
1541 
1542 	as = filp->private_data;
1543 	if (check_apm_user(as, "release"))
1544 		return 0;
1545 	filp->private_data = NULL;
1546 	if (as->standbys_pending > 0) {
1547 		standbys_pending -= as->standbys_pending;
1548 		if (standbys_pending <= 0)
1549 			standby();
1550 	}
1551 	if (as->suspends_pending > 0) {
1552 		suspends_pending -= as->suspends_pending;
1553 		if (suspends_pending <= 0)
1554 			(void) suspend(1);
1555 	}
1556 	spin_lock(&user_list_lock);
1557 	if (user_list == as)
1558 		user_list = as->next;
1559 	else {
1560 		struct apm_user *as1;
1561 
1562 		for (as1 = user_list;
1563 		     (as1 != NULL) && (as1->next != as);
1564 		     as1 = as1->next)
1565 			;
1566 		if (as1 == NULL)
1567 			pr_err("filp not in user list\n");
1568 		else
1569 			as1->next = as->next;
1570 	}
1571 	spin_unlock(&user_list_lock);
1572 	kfree(as);
1573 	return 0;
1574 }
1575 
1576 static int do_open(struct inode *inode, struct file *filp)
1577 {
1578 	struct apm_user *as;
1579 
1580 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1581 	if (as == NULL)
1582 		return -ENOMEM;
1583 
1584 	as->magic = APM_BIOS_MAGIC;
1585 	as->event_tail = as->event_head = 0;
1586 	as->suspends_pending = as->standbys_pending = 0;
1587 	as->suspends_read = as->standbys_read = 0;
1588 	/*
1589 	 * XXX - this is a tiny bit broken, when we consider BSD
1590 	 * process accounting. If the device is opened by root, we
1591 	 * instantly flag that we used superuser privs. Who knows,
1592 	 * we might close the device immediately without doing a
1593 	 * privileged operation -- cevans
1594 	 */
1595 	as->suser = capable(CAP_SYS_ADMIN);
1596 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1597 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1598 	spin_lock(&user_list_lock);
1599 	as->next = user_list;
1600 	user_list = as;
1601 	spin_unlock(&user_list_lock);
1602 	filp->private_data = as;
1603 	return 0;
1604 }
1605 
1606 #ifdef CONFIG_PROC_FS
1607 static int proc_apm_show(struct seq_file *m, void *v)
1608 {
1609 	unsigned short	bx;
1610 	unsigned short	cx;
1611 	unsigned short	dx;
1612 	int		error;
1613 	unsigned short  ac_line_status = 0xff;
1614 	unsigned short  battery_status = 0xff;
1615 	unsigned short  battery_flag   = 0xff;
1616 	int		percentage     = -1;
1617 	int             time_units     = -1;
1618 	char            *units         = "?";
1619 
1620 	if ((num_online_cpus() == 1) &&
1621 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1622 		ac_line_status = (bx >> 8) & 0xff;
1623 		battery_status = bx & 0xff;
1624 		if ((cx & 0xff) != 0xff)
1625 			percentage = cx & 0xff;
1626 
1627 		if (apm_info.connection_version > 0x100) {
1628 			battery_flag = (cx >> 8) & 0xff;
1629 			if (dx != 0xffff) {
1630 				units = (dx & 0x8000) ? "min" : "sec";
1631 				time_units = dx & 0x7fff;
1632 			}
1633 		}
1634 	}
1635 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1636 	   from the Get Power Status (0x0a) call unless otherwise noted.
1637 
1638 	   0) Linux driver version (this will change if format changes)
1639 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1640 	   2) APM flags from APM Installation Check (0x00):
1641 	      bit 0: APM_16_BIT_SUPPORT
1642 	      bit 1: APM_32_BIT_SUPPORT
1643 	      bit 2: APM_IDLE_SLOWS_CLOCK
1644 	      bit 3: APM_BIOS_DISABLED
1645 	      bit 4: APM_BIOS_DISENGAGED
1646 	   3) AC line status
1647 	      0x00: Off-line
1648 	      0x01: On-line
1649 	      0x02: On backup power (BIOS >= 1.1 only)
1650 	      0xff: Unknown
1651 	   4) Battery status
1652 	      0x00: High
1653 	      0x01: Low
1654 	      0x02: Critical
1655 	      0x03: Charging
1656 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1657 	      0xff: Unknown
1658 	   5) Battery flag
1659 	      bit 0: High
1660 	      bit 1: Low
1661 	      bit 2: Critical
1662 	      bit 3: Charging
1663 	      bit 7: No system battery
1664 	      0xff: Unknown
1665 	   6) Remaining battery life (percentage of charge):
1666 	      0-100: valid
1667 	      -1: Unknown
1668 	   7) Remaining battery life (time units):
1669 	      Number of remaining minutes or seconds
1670 	      -1: Unknown
1671 	   8) min = minutes; sec = seconds */
1672 
1673 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1674 		   driver_version,
1675 		   (apm_info.bios.version >> 8) & 0xff,
1676 		   apm_info.bios.version & 0xff,
1677 		   apm_info.bios.flags,
1678 		   ac_line_status,
1679 		   battery_status,
1680 		   battery_flag,
1681 		   percentage,
1682 		   time_units,
1683 		   units);
1684 	return 0;
1685 }
1686 #endif
1687 
1688 static int apm(void *unused)
1689 {
1690 	unsigned short	bx;
1691 	unsigned short	cx;
1692 	unsigned short	dx;
1693 	int		error;
1694 	char 		*power_stat;
1695 	char 		*bat_stat;
1696 
1697 	/* 2002/08/01 - WT
1698 	 * This is to avoid random crashes at boot time during initialization
1699 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1700 	 * Some bioses don't like being called from CPU != 0.
1701 	 * Method suggested by Ingo Molnar.
1702 	 */
1703 	set_cpus_allowed_ptr(current, cpumask_of(0));
1704 	BUG_ON(smp_processor_id() != 0);
1705 
1706 	if (apm_info.connection_version == 0) {
1707 		apm_info.connection_version = apm_info.bios.version;
1708 		if (apm_info.connection_version > 0x100) {
1709 			/*
1710 			 * We only support BIOSs up to version 1.2
1711 			 */
1712 			if (apm_info.connection_version > 0x0102)
1713 				apm_info.connection_version = 0x0102;
1714 			error = apm_driver_version(&apm_info.connection_version);
1715 			if (error != APM_SUCCESS) {
1716 				apm_error("driver version", error);
1717 				/* Fall back to an APM 1.0 connection. */
1718 				apm_info.connection_version = 0x100;
1719 			}
1720 		}
1721 	}
1722 
1723 	if (debug)
1724 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1725 			(apm_info.connection_version >> 8) & 0xff,
1726 			apm_info.connection_version & 0xff);
1727 
1728 #ifdef CONFIG_APM_DO_ENABLE
1729 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1730 		/*
1731 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1732 		 * is booted with PM disabled but not in the docking station.
1733 		 * Unfortunate ...
1734 		 */
1735 		error = apm_enable_power_management(1);
1736 		if (error) {
1737 			apm_error("enable power management", error);
1738 			return -1;
1739 		}
1740 	}
1741 #endif
1742 
1743 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1744 	    && (apm_info.connection_version > 0x0100)) {
1745 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1746 		if (error) {
1747 			apm_error("engage power management", error);
1748 			return -1;
1749 		}
1750 	}
1751 
1752 	if (debug && (num_online_cpus() == 1 || smp)) {
1753 		error = apm_get_power_status(&bx, &cx, &dx);
1754 		if (error)
1755 			printk(KERN_INFO "apm: power status not available\n");
1756 		else {
1757 			switch ((bx >> 8) & 0xff) {
1758 			case 0:
1759 				power_stat = "off line";
1760 				break;
1761 			case 1:
1762 				power_stat = "on line";
1763 				break;
1764 			case 2:
1765 				power_stat = "on backup power";
1766 				break;
1767 			default:
1768 				power_stat = "unknown";
1769 				break;
1770 			}
1771 			switch (bx & 0xff) {
1772 			case 0:
1773 				bat_stat = "high";
1774 				break;
1775 			case 1:
1776 				bat_stat = "low";
1777 				break;
1778 			case 2:
1779 				bat_stat = "critical";
1780 				break;
1781 			case 3:
1782 				bat_stat = "charging";
1783 				break;
1784 			default:
1785 				bat_stat = "unknown";
1786 				break;
1787 			}
1788 			printk(KERN_INFO
1789 			       "apm: AC %s, battery status %s, battery life ",
1790 			       power_stat, bat_stat);
1791 			if ((cx & 0xff) == 0xff)
1792 				printk("unknown\n");
1793 			else
1794 				printk("%d%%\n", cx & 0xff);
1795 			if (apm_info.connection_version > 0x100) {
1796 				printk(KERN_INFO
1797 				       "apm: battery flag 0x%02x, battery life ",
1798 				       (cx >> 8) & 0xff);
1799 				if (dx == 0xffff)
1800 					printk("unknown\n");
1801 				else
1802 					printk("%d %s\n", dx & 0x7fff,
1803 					       (dx & 0x8000) ?
1804 					       "minutes" : "seconds");
1805 			}
1806 		}
1807 	}
1808 
1809 	/* Install our power off handler.. */
1810 	if (power_off)
1811 		pm_power_off = apm_power_off;
1812 
1813 	if (num_online_cpus() == 1 || smp) {
1814 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1815 		console_blank_hook = apm_console_blank;
1816 #endif
1817 		apm_mainloop();
1818 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1819 		console_blank_hook = NULL;
1820 #endif
1821 	}
1822 
1823 	return 0;
1824 }
1825 
1826 #ifndef MODULE
1827 static int __init apm_setup(char *str)
1828 {
1829 	int invert;
1830 
1831 	while ((str != NULL) && (*str != '\0')) {
1832 		if (strncmp(str, "off", 3) == 0)
1833 			apm_disabled = 1;
1834 		if (strncmp(str, "on", 2) == 0)
1835 			apm_disabled = 0;
1836 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1837 		    (strncmp(str, "bounce_interval=", 16) == 0))
1838 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1839 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1840 		    (strncmp(str, "idle_threshold=", 15) == 0))
1841 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1842 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1843 		    (strncmp(str, "idle_period=", 12) == 0))
1844 			idle_period = simple_strtol(str + 12, NULL, 0);
1845 		invert = (strncmp(str, "no-", 3) == 0) ||
1846 			(strncmp(str, "no_", 3) == 0);
1847 		if (invert)
1848 			str += 3;
1849 		if (strncmp(str, "debug", 5) == 0)
1850 			debug = !invert;
1851 		if ((strncmp(str, "power-off", 9) == 0) ||
1852 		    (strncmp(str, "power_off", 9) == 0))
1853 			power_off = !invert;
1854 		if (strncmp(str, "smp", 3) == 0) {
1855 			smp = !invert;
1856 			idle_threshold = 100;
1857 		}
1858 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1859 		    (strncmp(str, "allow_ints", 10) == 0))
1860 			apm_info.allow_ints = !invert;
1861 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1862 		    (strncmp(str, "broken_psr", 10) == 0))
1863 			apm_info.get_power_status_broken = !invert;
1864 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1865 		    (strncmp(str, "realmode_power_off", 18) == 0))
1866 			apm_info.realmode_power_off = !invert;
1867 		str = strchr(str, ',');
1868 		if (str != NULL)
1869 			str += strspn(str, ", \t");
1870 	}
1871 	return 1;
1872 }
1873 
1874 __setup("apm=", apm_setup);
1875 #endif
1876 
1877 static const struct file_operations apm_bios_fops = {
1878 	.owner		= THIS_MODULE,
1879 	.read		= do_read,
1880 	.poll		= do_poll,
1881 	.unlocked_ioctl	= do_ioctl,
1882 	.open		= do_open,
1883 	.release	= do_release,
1884 	.llseek		= noop_llseek,
1885 };
1886 
1887 static struct miscdevice apm_device = {
1888 	APM_MINOR_DEV,
1889 	"apm_bios",
1890 	&apm_bios_fops
1891 };
1892 
1893 
1894 /* Simple "print if true" callback */
1895 static int __init print_if_true(const struct dmi_system_id *d)
1896 {
1897 	printk("%s\n", d->ident);
1898 	return 0;
1899 }
1900 
1901 /*
1902  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1903  * disabled before the suspend. Linux used to get terribly confused by that.
1904  */
1905 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1906 {
1907 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1908 	       "workaround hopefully not needed.\n", d->ident);
1909 	return 0;
1910 }
1911 
1912 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1913 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1914 {
1915 	if (apm_info.realmode_power_off == 0) {
1916 		apm_info.realmode_power_off = 1;
1917 		printk(KERN_INFO "%s bios detected. "
1918 		       "Using realmode poweroff only.\n", d->ident);
1919 	}
1920 	return 0;
1921 }
1922 
1923 /* Some laptops require interrupts to be enabled during APM calls */
1924 static int __init set_apm_ints(const struct dmi_system_id *d)
1925 {
1926 	if (apm_info.allow_ints == 0) {
1927 		apm_info.allow_ints = 1;
1928 		printk(KERN_INFO "%s machine detected. "
1929 		       "Enabling interrupts during APM calls.\n", d->ident);
1930 	}
1931 	return 0;
1932 }
1933 
1934 /* Some APM bioses corrupt memory or just plain do not work */
1935 static int __init apm_is_horked(const struct dmi_system_id *d)
1936 {
1937 	if (apm_info.disabled == 0) {
1938 		apm_info.disabled = 1;
1939 		printk(KERN_INFO "%s machine detected. "
1940 		       "Disabling APM.\n", d->ident);
1941 	}
1942 	return 0;
1943 }
1944 
1945 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1946 {
1947 	if (apm_info.disabled == 0) {
1948 		apm_info.disabled = 1;
1949 		printk(KERN_INFO "%s machine detected. "
1950 		       "Disabling APM.\n", d->ident);
1951 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1952 		printk(KERN_INFO "download from support.intel.com\n");
1953 	}
1954 	return 0;
1955 }
1956 
1957 /* Some APM bioses hang on APM idle calls */
1958 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1959 {
1960 	if (apm_info.forbid_idle == 0) {
1961 		apm_info.forbid_idle = 1;
1962 		printk(KERN_INFO "%s machine detected. "
1963 		       "Disabling APM idle calls.\n", d->ident);
1964 	}
1965 	return 0;
1966 }
1967 
1968 /*
1969  *  Check for clue free BIOS implementations who use
1970  *  the following QA technique
1971  *
1972  *      [ Write BIOS Code ]<------
1973  *               |                ^
1974  *      < Does it Compile >----N--
1975  *               |Y               ^
1976  *	< Does it Boot Win98 >-N--
1977  *               |Y
1978  *           [Ship It]
1979  *
1980  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
1981  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
1982  */
1983 static int __init broken_apm_power(const struct dmi_system_id *d)
1984 {
1985 	apm_info.get_power_status_broken = 1;
1986 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
1987 	       "disabling power status reporting.\n");
1988 	return 0;
1989 }
1990 
1991 /*
1992  * This bios swaps the APM minute reporting bytes over (Many sony laptops
1993  * have this problem).
1994  */
1995 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
1996 {
1997 	apm_info.get_power_status_swabinminutes = 1;
1998 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
1999 	       "in minutes and wrong byte order.\n");
2000 	return 0;
2001 }
2002 
2003 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2004 	{
2005 		print_if_true,
2006 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2007 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2008 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2009 	},
2010 	{	/* Handle problems with APM on the C600 */
2011 		broken_ps2_resume, "Dell Latitude C600",
2012 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2013 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2014 	},
2015 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2016 		set_apm_ints, "Dell Latitude",
2017 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2018 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2019 	},
2020 	{	/* APM crashes */
2021 		apm_is_horked, "Dell Inspiron 2500",
2022 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2023 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2024 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2025 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2026 	},
2027 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2028 		set_apm_ints, "Dell Inspiron", {
2029 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2030 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2031 	},
2032 	{	/* Handle problems with APM on Inspiron 5000e */
2033 		broken_apm_power, "Dell Inspiron 5000e",
2034 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2035 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2036 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2037 	},
2038 	{	/* Handle problems with APM on Inspiron 2500 */
2039 		broken_apm_power, "Dell Inspiron 2500",
2040 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2041 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2042 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2043 	},
2044 	{	/* APM crashes */
2045 		apm_is_horked, "Dell Dimension 4100",
2046 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2047 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2048 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2049 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2050 	},
2051 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2052 		set_apm_ints, "Compaq 12XL125",
2053 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2054 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2055 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2056 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2057 	},
2058 	{	/* Allow interrupts during APM or the clock goes slow */
2059 		set_apm_ints, "ASUSTeK",
2060 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2061 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2062 	},
2063 	{	/* APM blows on shutdown */
2064 		apm_is_horked, "ABIT KX7-333[R]",
2065 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2066 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2067 	},
2068 	{	/* APM crashes */
2069 		apm_is_horked, "Trigem Delhi3",
2070 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2071 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2072 	},
2073 	{	/* APM crashes */
2074 		apm_is_horked, "Fujitsu-Siemens",
2075 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2076 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2077 	},
2078 	{	/* APM crashes */
2079 		apm_is_horked_d850md, "Intel D850MD",
2080 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2081 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2082 	},
2083 	{	/* APM crashes */
2084 		apm_is_horked, "Intel D810EMO",
2085 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2086 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2087 	},
2088 	{	/* APM crashes */
2089 		apm_is_horked, "Dell XPS-Z",
2090 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2091 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2092 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2093 	},
2094 	{	/* APM crashes */
2095 		apm_is_horked, "Sharp PC-PJ/AX",
2096 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2097 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2098 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2099 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2100 	},
2101 	{	/* APM crashes */
2102 		apm_is_horked, "Dell Inspiron 2500",
2103 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2104 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2105 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2106 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2107 	},
2108 	{	/* APM idle hangs */
2109 		apm_likes_to_melt, "Jabil AMD",
2110 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2111 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2112 	},
2113 	{	/* APM idle hangs */
2114 		apm_likes_to_melt, "AMI Bios",
2115 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2116 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2117 	},
2118 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2119 		swab_apm_power_in_minutes, "Sony VAIO",
2120 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2121 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2122 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2123 	},
2124 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2125 		swab_apm_power_in_minutes, "Sony VAIO",
2126 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2127 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2128 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2129 	},
2130 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2131 		swab_apm_power_in_minutes, "Sony VAIO",
2132 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2133 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2134 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2135 	},
2136 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2137 		swab_apm_power_in_minutes, "Sony VAIO",
2138 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2139 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2140 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2141 	},
2142 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2143 		swab_apm_power_in_minutes, "Sony VAIO",
2144 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2145 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2146 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2147 	},
2148 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2149 		swab_apm_power_in_minutes, "Sony VAIO",
2150 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2151 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2152 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2153 	},
2154 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2155 		swab_apm_power_in_minutes, "Sony VAIO",
2156 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2157 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2158 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2159 	},
2160 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2161 		swab_apm_power_in_minutes, "Sony VAIO",
2162 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2163 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2164 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2165 	},
2166 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2167 		swab_apm_power_in_minutes, "Sony VAIO",
2168 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2169 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2170 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2171 	},
2172 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2173 		swab_apm_power_in_minutes, "Sony VAIO",
2174 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2175 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2176 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2177 	},
2178 
2179 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2180 		swab_apm_power_in_minutes, "Sony VAIO",
2181 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2182 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2183 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2184 	},
2185 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2186 		swab_apm_power_in_minutes, "Sony VAIO",
2187 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2188 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2189 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2190 	},
2191 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2192 		swab_apm_power_in_minutes, "Sony VAIO",
2193 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2194 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2195 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2196 	},
2197 	{	/* broken PM poweroff bios */
2198 		set_realmode_power_off, "Award Software v4.60 PGMA",
2199 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2200 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2201 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2202 	},
2203 
2204 	/* Generic per vendor APM settings  */
2205 
2206 	{	/* Allow interrupts during suspend on IBM laptops */
2207 		set_apm_ints, "IBM",
2208 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2209 	},
2210 
2211 	{ }
2212 };
2213 
2214 /*
2215  * Just start the APM thread. We do NOT want to do APM BIOS
2216  * calls from anything but the APM thread, if for no other reason
2217  * than the fact that we don't trust the APM BIOS. This way,
2218  * most common APM BIOS problems that lead to protection errors
2219  * etc will have at least some level of being contained...
2220  *
2221  * In short, if something bad happens, at least we have a choice
2222  * of just killing the apm thread..
2223  */
2224 static int __init apm_init(void)
2225 {
2226 	struct desc_struct *gdt;
2227 	int err;
2228 
2229 	dmi_check_system(apm_dmi_table);
2230 
2231 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2232 		printk(KERN_INFO "apm: BIOS not found.\n");
2233 		return -ENODEV;
2234 	}
2235 	printk(KERN_INFO
2236 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2237 	       ((apm_info.bios.version >> 8) & 0xff),
2238 	       (apm_info.bios.version & 0xff),
2239 	       apm_info.bios.flags,
2240 	       driver_version);
2241 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2242 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2243 		return -ENODEV;
2244 	}
2245 
2246 	if (allow_ints)
2247 		apm_info.allow_ints = 1;
2248 	if (broken_psr)
2249 		apm_info.get_power_status_broken = 1;
2250 	if (realmode_power_off)
2251 		apm_info.realmode_power_off = 1;
2252 	/* User can override, but default is to trust DMI */
2253 	if (apm_disabled != -1)
2254 		apm_info.disabled = apm_disabled;
2255 
2256 	/*
2257 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2258 	 * but is reportedly a 1.0 BIOS.
2259 	 */
2260 	if (apm_info.bios.version == 0x001)
2261 		apm_info.bios.version = 0x100;
2262 
2263 	/* BIOS < 1.2 doesn't set cseg_16_len */
2264 	if (apm_info.bios.version < 0x102)
2265 		apm_info.bios.cseg_16_len = 0; /* 64k */
2266 
2267 	if (debug) {
2268 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2269 			apm_info.bios.cseg, apm_info.bios.offset,
2270 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2271 		if (apm_info.bios.version > 0x100)
2272 			printk(" cseg len %x, dseg len %x",
2273 				apm_info.bios.cseg_len,
2274 				apm_info.bios.dseg_len);
2275 		if (apm_info.bios.version > 0x101)
2276 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2277 		printk("\n");
2278 	}
2279 
2280 	if (apm_info.disabled) {
2281 		pr_notice("disabled on user request.\n");
2282 		return -ENODEV;
2283 	}
2284 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2285 		pr_notice("disabled - APM is not SMP safe.\n");
2286 		apm_info.disabled = 1;
2287 		return -ENODEV;
2288 	}
2289 	if (!acpi_disabled) {
2290 		pr_notice("overridden by ACPI.\n");
2291 		apm_info.disabled = 1;
2292 		return -ENODEV;
2293 	}
2294 
2295 	/*
2296 	 * Set up the long jump entry point to the APM BIOS, which is called
2297 	 * from inline assembly.
2298 	 */
2299 	apm_bios_entry.offset = apm_info.bios.offset;
2300 	apm_bios_entry.segment = APM_CS;
2301 
2302 	/*
2303 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2304 	 * recognizes.  Many machines do this correctly, but many others do
2305 	 * not restrict themselves to their claimed limit.  When this happens,
2306 	 * they will cause a segmentation violation in the kernel at boot time.
2307 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2308 	 *
2309 	 * Note we only set APM segments on CPU zero, since we pin the APM
2310 	 * code to that CPU.
2311 	 */
2312 	gdt = get_cpu_gdt_rw(0);
2313 	set_desc_base(&gdt[APM_CS >> 3],
2314 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2315 	set_desc_base(&gdt[APM_CS_16 >> 3],
2316 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2317 	set_desc_base(&gdt[APM_DS >> 3],
2318 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2319 
2320 	proc_create_single("apm", 0, NULL, proc_apm_show);
2321 
2322 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2323 	if (IS_ERR(kapmd_task)) {
2324 		pr_err("disabled - Unable to start kernel thread\n");
2325 		err = PTR_ERR(kapmd_task);
2326 		kapmd_task = NULL;
2327 		remove_proc_entry("apm", NULL);
2328 		return err;
2329 	}
2330 	wake_up_process(kapmd_task);
2331 
2332 	if (num_online_cpus() > 1 && !smp) {
2333 		printk(KERN_NOTICE
2334 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2335 		return 0;
2336 	}
2337 
2338 	/*
2339 	 * Note we don't actually care if the misc_device cannot be registered.
2340 	 * this driver can do its job without it, even if userspace can't
2341 	 * control it.  just log the error
2342 	 */
2343 	if (misc_register(&apm_device))
2344 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2345 
2346 	if (HZ != 100)
2347 		idle_period = (idle_period * HZ) / 100;
2348 	if (idle_threshold < 100) {
2349 		cpuidle_poll_state_init(&apm_idle_driver);
2350 		if (!cpuidle_register_driver(&apm_idle_driver))
2351 			if (cpuidle_register_device(&apm_cpuidle_device))
2352 				cpuidle_unregister_driver(&apm_idle_driver);
2353 	}
2354 
2355 	return 0;
2356 }
2357 
2358 static void __exit apm_exit(void)
2359 {
2360 	int error;
2361 
2362 	cpuidle_unregister_device(&apm_cpuidle_device);
2363 	cpuidle_unregister_driver(&apm_idle_driver);
2364 
2365 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2366 	    && (apm_info.connection_version > 0x0100)) {
2367 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2368 		if (error)
2369 			apm_error("disengage power management", error);
2370 	}
2371 	misc_deregister(&apm_device);
2372 	remove_proc_entry("apm", NULL);
2373 	if (power_off)
2374 		pm_power_off = NULL;
2375 	if (kapmd_task) {
2376 		kthread_stop(kapmd_task);
2377 		kapmd_task = NULL;
2378 	}
2379 }
2380 
2381 module_init(apm_init);
2382 module_exit(apm_exit);
2383 
2384 MODULE_AUTHOR("Stephen Rothwell");
2385 MODULE_DESCRIPTION("Advanced Power Management");
2386 MODULE_LICENSE("GPL");
2387 module_param(debug, bool, 0644);
2388 MODULE_PARM_DESC(debug, "Enable debug mode");
2389 module_param(power_off, bool, 0444);
2390 MODULE_PARM_DESC(power_off, "Enable power off");
2391 module_param(bounce_interval, int, 0444);
2392 MODULE_PARM_DESC(bounce_interval,
2393 		"Set the number of ticks to ignore suspend bounces");
2394 module_param(allow_ints, bool, 0444);
2395 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2396 module_param(broken_psr, bool, 0444);
2397 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2398 module_param(realmode_power_off, bool, 0444);
2399 MODULE_PARM_DESC(realmode_power_off,
2400 		"Switch to real mode before powering off");
2401 module_param(idle_threshold, int, 0444);
2402 MODULE_PARM_DESC(idle_threshold,
2403 	"System idle percentage above which to make APM BIOS idle calls");
2404 module_param(idle_period, int, 0444);
2405 MODULE_PARM_DESC(idle_period,
2406 	"Period (in sec/100) over which to calculate the idle percentage");
2407 module_param(smp, bool, 0444);
2408 MODULE_PARM_DESC(smp,
2409 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2410 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2411