xref: /linux/drivers/acpi/sleep.c (revision d229807f669ba3dea9f64467ee965051c4366aed)
1 /*
2  * sleep.c - ACPI sleep support.
3  *
4  * Copyright (c) 2005 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
5  * Copyright (c) 2004 David Shaohua Li <shaohua.li@intel.com>
6  * Copyright (c) 2000-2003 Patrick Mochel
7  * Copyright (c) 2003 Open Source Development Lab
8  *
9  * This file is released under the GPLv2.
10  *
11  */
12 
13 #include <linux/delay.h>
14 #include <linux/irq.h>
15 #include <linux/dmi.h>
16 #include <linux/device.h>
17 #include <linux/suspend.h>
18 #include <linux/reboot.h>
19 #include <linux/acpi.h>
20 
21 #include <asm/io.h>
22 
23 #include <acpi/acpi_bus.h>
24 #include <acpi/acpi_drivers.h>
25 
26 #include "internal.h"
27 #include "sleep.h"
28 
29 static u8 sleep_states[ACPI_S_STATE_COUNT];
30 
31 static void acpi_sleep_tts_switch(u32 acpi_state)
32 {
33 	union acpi_object in_arg = { ACPI_TYPE_INTEGER };
34 	struct acpi_object_list arg_list = { 1, &in_arg };
35 	acpi_status status = AE_OK;
36 
37 	in_arg.integer.value = acpi_state;
38 	status = acpi_evaluate_object(NULL, "\\_TTS", &arg_list, NULL);
39 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
40 		/*
41 		 * OS can't evaluate the _TTS object correctly. Some warning
42 		 * message will be printed. But it won't break anything.
43 		 */
44 		printk(KERN_NOTICE "Failure in evaluating _TTS object\n");
45 	}
46 }
47 
48 static int tts_notify_reboot(struct notifier_block *this,
49 			unsigned long code, void *x)
50 {
51 	acpi_sleep_tts_switch(ACPI_STATE_S5);
52 	return NOTIFY_DONE;
53 }
54 
55 static struct notifier_block tts_notifier = {
56 	.notifier_call	= tts_notify_reboot,
57 	.next		= NULL,
58 	.priority	= 0,
59 };
60 
61 static int acpi_sleep_prepare(u32 acpi_state)
62 {
63 #ifdef CONFIG_ACPI_SLEEP
64 	/* do we have a wakeup address for S2 and S3? */
65 	if (acpi_state == ACPI_STATE_S3) {
66 		if (!acpi_wakeup_address) {
67 			return -EFAULT;
68 		}
69 		acpi_set_firmware_waking_vector(
70 				(acpi_physical_address)acpi_wakeup_address);
71 
72 	}
73 	ACPI_FLUSH_CPU_CACHE();
74 #endif
75 	printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
76 		acpi_state);
77 	acpi_enable_wakeup_devices(acpi_state);
78 	acpi_enter_sleep_state_prep(acpi_state);
79 	return 0;
80 }
81 
82 #ifdef CONFIG_ACPI_SLEEP
83 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
84 
85 /*
86  * The ACPI specification wants us to save NVS memory regions during hibernation
87  * and to restore them during the subsequent resume.  Windows does that also for
88  * suspend to RAM.  However, it is known that this mechanism does not work on
89  * all machines, so we allow the user to disable it with the help of the
90  * 'acpi_sleep=nonvs' kernel command line option.
91  */
92 static bool nvs_nosave;
93 
94 void __init acpi_nvs_nosave(void)
95 {
96 	nvs_nosave = true;
97 }
98 
99 /*
100  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
101  * user to request that behavior by using the 'acpi_old_suspend_ordering'
102  * kernel command line option that causes the following variable to be set.
103  */
104 static bool old_suspend_ordering;
105 
106 void __init acpi_old_suspend_ordering(void)
107 {
108 	old_suspend_ordering = true;
109 }
110 
111 /**
112  * acpi_pm_freeze - Disable the GPEs and suspend EC transactions.
113  */
114 static int acpi_pm_freeze(void)
115 {
116 	acpi_disable_all_gpes();
117 	acpi_os_wait_events_complete(NULL);
118 	acpi_ec_block_transactions();
119 	return 0;
120 }
121 
122 /**
123  * acpi_pre_suspend - Enable wakeup devices, "freeze" EC and save NVS.
124  */
125 static int acpi_pm_pre_suspend(void)
126 {
127 	acpi_pm_freeze();
128 	return suspend_nvs_save();
129 }
130 
131 /**
132  *	__acpi_pm_prepare - Prepare the platform to enter the target state.
133  *
134  *	If necessary, set the firmware waking vector and do arch-specific
135  *	nastiness to get the wakeup code to the waking vector.
136  */
137 static int __acpi_pm_prepare(void)
138 {
139 	int error = acpi_sleep_prepare(acpi_target_sleep_state);
140 	if (error)
141 		acpi_target_sleep_state = ACPI_STATE_S0;
142 
143 	return error;
144 }
145 
146 /**
147  *	acpi_pm_prepare - Prepare the platform to enter the target sleep
148  *		state and disable the GPEs.
149  */
150 static int acpi_pm_prepare(void)
151 {
152 	int error = __acpi_pm_prepare();
153 	if (!error)
154 		error = acpi_pm_pre_suspend();
155 
156 	return error;
157 }
158 
159 /**
160  *	acpi_pm_finish - Instruct the platform to leave a sleep state.
161  *
162  *	This is called after we wake back up (or if entering the sleep state
163  *	failed).
164  */
165 static void acpi_pm_finish(void)
166 {
167 	u32 acpi_state = acpi_target_sleep_state;
168 
169 	acpi_ec_unblock_transactions();
170 	suspend_nvs_free();
171 
172 	if (acpi_state == ACPI_STATE_S0)
173 		return;
174 
175 	printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
176 		acpi_state);
177 	acpi_disable_wakeup_devices(acpi_state);
178 	acpi_leave_sleep_state(acpi_state);
179 
180 	/* reset firmware waking vector */
181 	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
182 
183 	acpi_target_sleep_state = ACPI_STATE_S0;
184 }
185 
186 /**
187  *	acpi_pm_end - Finish up suspend sequence.
188  */
189 static void acpi_pm_end(void)
190 {
191 	/*
192 	 * This is necessary in case acpi_pm_finish() is not called during a
193 	 * failing transition to a sleep state.
194 	 */
195 	acpi_target_sleep_state = ACPI_STATE_S0;
196 	acpi_sleep_tts_switch(acpi_target_sleep_state);
197 }
198 #else /* !CONFIG_ACPI_SLEEP */
199 #define acpi_target_sleep_state	ACPI_STATE_S0
200 #endif /* CONFIG_ACPI_SLEEP */
201 
202 #ifdef CONFIG_SUSPEND
203 static u32 acpi_suspend_states[] = {
204 	[PM_SUSPEND_ON] = ACPI_STATE_S0,
205 	[PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
206 	[PM_SUSPEND_MEM] = ACPI_STATE_S3,
207 	[PM_SUSPEND_MAX] = ACPI_STATE_S5
208 };
209 
210 /**
211  *	acpi_suspend_begin - Set the target system sleep state to the state
212  *		associated with given @pm_state, if supported.
213  */
214 static int acpi_suspend_begin(suspend_state_t pm_state)
215 {
216 	u32 acpi_state = acpi_suspend_states[pm_state];
217 	int error = 0;
218 
219 	error = nvs_nosave ? 0 : suspend_nvs_alloc();
220 	if (error)
221 		return error;
222 
223 	if (sleep_states[acpi_state]) {
224 		acpi_target_sleep_state = acpi_state;
225 		acpi_sleep_tts_switch(acpi_target_sleep_state);
226 	} else {
227 		printk(KERN_ERR "ACPI does not support this state: %d\n",
228 			pm_state);
229 		error = -ENOSYS;
230 	}
231 	return error;
232 }
233 
234 /**
235  *	acpi_suspend_enter - Actually enter a sleep state.
236  *	@pm_state: ignored
237  *
238  *	Flush caches and go to sleep. For STR we have to call arch-specific
239  *	assembly, which in turn call acpi_enter_sleep_state().
240  *	It's unfortunate, but it works. Please fix if you're feeling frisky.
241  */
242 static int acpi_suspend_enter(suspend_state_t pm_state)
243 {
244 	acpi_status status = AE_OK;
245 	u32 acpi_state = acpi_target_sleep_state;
246 	int error;
247 
248 	ACPI_FLUSH_CPU_CACHE();
249 
250 	switch (acpi_state) {
251 	case ACPI_STATE_S1:
252 		barrier();
253 		status = acpi_enter_sleep_state(acpi_state);
254 		break;
255 
256 	case ACPI_STATE_S3:
257 		error = acpi_suspend_lowlevel();
258 		if (error)
259 			return error;
260 		pr_info(PREFIX "Low-level resume complete\n");
261 		break;
262 	}
263 
264 	/* This violates the spec but is required for bug compatibility. */
265 	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
266 
267 	/* Reprogram control registers and execute _BFS */
268 	acpi_leave_sleep_state_prep(acpi_state);
269 
270 	/* ACPI 3.0 specs (P62) says that it's the responsibility
271 	 * of the OSPM to clear the status bit [ implying that the
272 	 * POWER_BUTTON event should not reach userspace ]
273 	 */
274 	if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3))
275 		acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
276 
277 	/*
278 	 * Disable and clear GPE status before interrupt is enabled. Some GPEs
279 	 * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
280 	 * acpi_leave_sleep_state will reenable specific GPEs later
281 	 */
282 	acpi_disable_all_gpes();
283 	/* Allow EC transactions to happen. */
284 	acpi_ec_unblock_transactions_early();
285 
286 	suspend_nvs_restore();
287 
288 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
289 }
290 
291 static int acpi_suspend_state_valid(suspend_state_t pm_state)
292 {
293 	u32 acpi_state;
294 
295 	switch (pm_state) {
296 	case PM_SUSPEND_ON:
297 	case PM_SUSPEND_STANDBY:
298 	case PM_SUSPEND_MEM:
299 		acpi_state = acpi_suspend_states[pm_state];
300 
301 		return sleep_states[acpi_state];
302 	default:
303 		return 0;
304 	}
305 }
306 
307 static const struct platform_suspend_ops acpi_suspend_ops = {
308 	.valid = acpi_suspend_state_valid,
309 	.begin = acpi_suspend_begin,
310 	.prepare_late = acpi_pm_prepare,
311 	.enter = acpi_suspend_enter,
312 	.wake = acpi_pm_finish,
313 	.end = acpi_pm_end,
314 };
315 
316 /**
317  *	acpi_suspend_begin_old - Set the target system sleep state to the
318  *		state associated with given @pm_state, if supported, and
319  *		execute the _PTS control method.  This function is used if the
320  *		pre-ACPI 2.0 suspend ordering has been requested.
321  */
322 static int acpi_suspend_begin_old(suspend_state_t pm_state)
323 {
324 	int error = acpi_suspend_begin(pm_state);
325 	if (!error)
326 		error = __acpi_pm_prepare();
327 
328 	return error;
329 }
330 
331 /*
332  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
333  * been requested.
334  */
335 static const struct platform_suspend_ops acpi_suspend_ops_old = {
336 	.valid = acpi_suspend_state_valid,
337 	.begin = acpi_suspend_begin_old,
338 	.prepare_late = acpi_pm_pre_suspend,
339 	.enter = acpi_suspend_enter,
340 	.wake = acpi_pm_finish,
341 	.end = acpi_pm_end,
342 	.recover = acpi_pm_finish,
343 };
344 
345 static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
346 {
347 	old_suspend_ordering = true;
348 	return 0;
349 }
350 
351 static int __init init_nvs_nosave(const struct dmi_system_id *d)
352 {
353 	acpi_nvs_nosave();
354 	return 0;
355 }
356 
357 static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
358 	{
359 	.callback = init_old_suspend_ordering,
360 	.ident = "Abit KN9 (nForce4 variant)",
361 	.matches = {
362 		DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
363 		DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
364 		},
365 	},
366 	{
367 	.callback = init_old_suspend_ordering,
368 	.ident = "HP xw4600 Workstation",
369 	.matches = {
370 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
371 		DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
372 		},
373 	},
374 	{
375 	.callback = init_old_suspend_ordering,
376 	.ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
377 	.matches = {
378 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTek Computer INC."),
379 		DMI_MATCH(DMI_BOARD_NAME, "M2N8L"),
380 		},
381 	},
382 	{
383 	.callback = init_old_suspend_ordering,
384 	.ident = "Panasonic CF51-2L",
385 	.matches = {
386 		DMI_MATCH(DMI_BOARD_VENDOR,
387 				"Matsushita Electric Industrial Co.,Ltd."),
388 		DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
389 		},
390 	},
391 	{
392 	.callback = init_nvs_nosave,
393 	.ident = "Sony Vaio VGN-FW21E",
394 	.matches = {
395 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
396 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21E"),
397 		},
398 	},
399 	{
400 	.callback = init_nvs_nosave,
401 	.ident = "Sony Vaio VGN-SR11M",
402 	.matches = {
403 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
404 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR11M"),
405 		},
406 	},
407 	{
408 	.callback = init_nvs_nosave,
409 	.ident = "Everex StepNote Series",
410 	.matches = {
411 		DMI_MATCH(DMI_SYS_VENDOR, "Everex Systems, Inc."),
412 		DMI_MATCH(DMI_PRODUCT_NAME, "Everex StepNote Series"),
413 		},
414 	},
415 	{
416 	.callback = init_nvs_nosave,
417 	.ident = "Sony Vaio VPCEB1Z1E",
418 	.matches = {
419 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
420 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1Z1E"),
421 		},
422 	},
423 	{
424 	.callback = init_nvs_nosave,
425 	.ident = "Sony Vaio VGN-NW130D",
426 	.matches = {
427 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
428 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-NW130D"),
429 		},
430 	},
431 	{
432 	.callback = init_nvs_nosave,
433 	.ident = "Averatec AV1020-ED2",
434 	.matches = {
435 		DMI_MATCH(DMI_SYS_VENDOR, "AVERATEC"),
436 		DMI_MATCH(DMI_PRODUCT_NAME, "1000 Series"),
437 		},
438 	},
439 	{
440 	.callback = init_old_suspend_ordering,
441 	.ident = "Asus A8N-SLI DELUXE",
442 	.matches = {
443 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
444 		DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI DELUXE"),
445 		},
446 	},
447 	{
448 	.callback = init_old_suspend_ordering,
449 	.ident = "Asus A8N-SLI Premium",
450 	.matches = {
451 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
452 		DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI Premium"),
453 		},
454 	},
455 	{
456 	.callback = init_nvs_nosave,
457 	.ident = "Sony Vaio VGN-SR26GN_P",
458 	.matches = {
459 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
460 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR26GN_P"),
461 		},
462 	},
463 	{
464 	.callback = init_nvs_nosave,
465 	.ident = "Sony Vaio VGN-FW520F",
466 	.matches = {
467 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
468 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW520F"),
469 		},
470 	},
471 	{},
472 };
473 #endif /* CONFIG_SUSPEND */
474 
475 #ifdef CONFIG_HIBERNATION
476 static unsigned long s4_hardware_signature;
477 static struct acpi_table_facs *facs;
478 static bool nosigcheck;
479 
480 void __init acpi_no_s4_hw_signature(void)
481 {
482 	nosigcheck = true;
483 }
484 
485 static int acpi_hibernation_begin(void)
486 {
487 	int error;
488 
489 	error = nvs_nosave ? 0 : suspend_nvs_alloc();
490 	if (!error) {
491 		acpi_target_sleep_state = ACPI_STATE_S4;
492 		acpi_sleep_tts_switch(acpi_target_sleep_state);
493 	}
494 
495 	return error;
496 }
497 
498 static int acpi_hibernation_enter(void)
499 {
500 	acpi_status status = AE_OK;
501 
502 	ACPI_FLUSH_CPU_CACHE();
503 
504 	/* This shouldn't return.  If it returns, we have a problem */
505 	status = acpi_enter_sleep_state(ACPI_STATE_S4);
506 	/* Reprogram control registers and execute _BFS */
507 	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
508 
509 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
510 }
511 
512 static void acpi_hibernation_leave(void)
513 {
514 	/*
515 	 * If ACPI is not enabled by the BIOS and the boot kernel, we need to
516 	 * enable it here.
517 	 */
518 	acpi_enable();
519 	/* Reprogram control registers and execute _BFS */
520 	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
521 	/* Check the hardware signature */
522 	if (facs && s4_hardware_signature != facs->hardware_signature) {
523 		printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
524 			"cannot resume!\n");
525 		panic("ACPI S4 hardware signature mismatch");
526 	}
527 	/* Restore the NVS memory area */
528 	suspend_nvs_restore();
529 	/* Allow EC transactions to happen. */
530 	acpi_ec_unblock_transactions_early();
531 }
532 
533 static void acpi_pm_thaw(void)
534 {
535 	acpi_ec_unblock_transactions();
536 	acpi_enable_all_runtime_gpes();
537 }
538 
539 static const struct platform_hibernation_ops acpi_hibernation_ops = {
540 	.begin = acpi_hibernation_begin,
541 	.end = acpi_pm_end,
542 	.pre_snapshot = acpi_pm_prepare,
543 	.finish = acpi_pm_finish,
544 	.prepare = acpi_pm_prepare,
545 	.enter = acpi_hibernation_enter,
546 	.leave = acpi_hibernation_leave,
547 	.pre_restore = acpi_pm_freeze,
548 	.restore_cleanup = acpi_pm_thaw,
549 };
550 
551 /**
552  *	acpi_hibernation_begin_old - Set the target system sleep state to
553  *		ACPI_STATE_S4 and execute the _PTS control method.  This
554  *		function is used if the pre-ACPI 2.0 suspend ordering has been
555  *		requested.
556  */
557 static int acpi_hibernation_begin_old(void)
558 {
559 	int error;
560 	/*
561 	 * The _TTS object should always be evaluated before the _PTS object.
562 	 * When the old_suspended_ordering is true, the _PTS object is
563 	 * evaluated in the acpi_sleep_prepare.
564 	 */
565 	acpi_sleep_tts_switch(ACPI_STATE_S4);
566 
567 	error = acpi_sleep_prepare(ACPI_STATE_S4);
568 
569 	if (!error) {
570 		if (!nvs_nosave)
571 			error = suspend_nvs_alloc();
572 		if (!error)
573 			acpi_target_sleep_state = ACPI_STATE_S4;
574 	}
575 	return error;
576 }
577 
578 /*
579  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
580  * been requested.
581  */
582 static const struct platform_hibernation_ops acpi_hibernation_ops_old = {
583 	.begin = acpi_hibernation_begin_old,
584 	.end = acpi_pm_end,
585 	.pre_snapshot = acpi_pm_pre_suspend,
586 	.prepare = acpi_pm_freeze,
587 	.finish = acpi_pm_finish,
588 	.enter = acpi_hibernation_enter,
589 	.leave = acpi_hibernation_leave,
590 	.pre_restore = acpi_pm_freeze,
591 	.restore_cleanup = acpi_pm_thaw,
592 	.recover = acpi_pm_finish,
593 };
594 #endif /* CONFIG_HIBERNATION */
595 
596 int acpi_suspend(u32 acpi_state)
597 {
598 	suspend_state_t states[] = {
599 		[1] = PM_SUSPEND_STANDBY,
600 		[3] = PM_SUSPEND_MEM,
601 		[5] = PM_SUSPEND_MAX
602 	};
603 
604 	if (acpi_state < 6 && states[acpi_state])
605 		return pm_suspend(states[acpi_state]);
606 	if (acpi_state == 4)
607 		return hibernate();
608 	return -EINVAL;
609 }
610 
611 #ifdef CONFIG_PM
612 /**
613  *	acpi_pm_device_sleep_state - return preferred power state of ACPI device
614  *		in the system sleep state given by %acpi_target_sleep_state
615  *	@dev: device to examine; its driver model wakeup flags control
616  *		whether it should be able to wake up the system
617  *	@d_min_p: used to store the upper limit of allowed states range
618  *	Return value: preferred power state of the device on success, -ENODEV on
619  *		failure (ie. if there's no 'struct acpi_device' for @dev)
620  *
621  *	Find the lowest power (highest number) ACPI device power state that
622  *	device @dev can be in while the system is in the sleep state represented
623  *	by %acpi_target_sleep_state.  If @wake is nonzero, the device should be
624  *	able to wake up the system from this sleep state.  If @d_min_p is set,
625  *	the highest power (lowest number) device power state of @dev allowed
626  *	in this system sleep state is stored at the location pointed to by it.
627  *
628  *	The caller must ensure that @dev is valid before using this function.
629  *	The caller is also responsible for figuring out if the device is
630  *	supposed to be able to wake up the system and passing this information
631  *	via @wake.
632  */
633 
634 int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p)
635 {
636 	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
637 	struct acpi_device *adev;
638 	char acpi_method[] = "_SxD";
639 	unsigned long long d_min, d_max;
640 
641 	if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
642 		printk(KERN_DEBUG "ACPI handle has no context!\n");
643 		return -ENODEV;
644 	}
645 
646 	acpi_method[2] = '0' + acpi_target_sleep_state;
647 	/*
648 	 * If the sleep state is S0, we will return D3, but if the device has
649 	 * _S0W, we will use the value from _S0W
650 	 */
651 	d_min = ACPI_STATE_D0;
652 	d_max = ACPI_STATE_D3;
653 
654 	/*
655 	 * If present, _SxD methods return the minimum D-state (highest power
656 	 * state) we can use for the corresponding S-states.  Otherwise, the
657 	 * minimum D-state is D0 (ACPI 3.x).
658 	 *
659 	 * NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
660 	 * provided -- that's our fault recovery, we ignore retval.
661 	 */
662 	if (acpi_target_sleep_state > ACPI_STATE_S0)
663 		acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);
664 
665 	/*
666 	 * If _PRW says we can wake up the system from the target sleep state,
667 	 * the D-state returned by _SxD is sufficient for that (we assume a
668 	 * wakeup-aware driver if wake is set).  Still, if _SxW exists
669 	 * (ACPI 3.x), it should return the maximum (lowest power) D-state that
670 	 * can wake the system.  _S0W may be valid, too.
671 	 */
672 	if (acpi_target_sleep_state == ACPI_STATE_S0 ||
673 	    (device_may_wakeup(dev) &&
674 	     adev->wakeup.sleep_state <= acpi_target_sleep_state)) {
675 		acpi_status status;
676 
677 		acpi_method[3] = 'W';
678 		status = acpi_evaluate_integer(handle, acpi_method, NULL,
679 						&d_max);
680 		if (ACPI_FAILURE(status)) {
681 			if (acpi_target_sleep_state != ACPI_STATE_S0 ||
682 			    status != AE_NOT_FOUND)
683 				d_max = d_min;
684 		} else if (d_max < d_min) {
685 			/* Warn the user of the broken DSDT */
686 			printk(KERN_WARNING "ACPI: Wrong value from %s\n",
687 				acpi_method);
688 			/* Sanitize it */
689 			d_min = d_max;
690 		}
691 	}
692 
693 	if (d_min_p)
694 		*d_min_p = d_min;
695 	return d_max;
696 }
697 #endif /* CONFIG_PM */
698 
699 #ifdef CONFIG_PM_SLEEP
700 /**
701  *	acpi_pm_device_sleep_wake - enable or disable the system wake-up
702  *                                  capability of given device
703  *	@dev: device to handle
704  *	@enable: 'true' - enable, 'false' - disable the wake-up capability
705  */
706 int acpi_pm_device_sleep_wake(struct device *dev, bool enable)
707 {
708 	acpi_handle handle;
709 	struct acpi_device *adev;
710 	int error;
711 
712 	if (!device_can_wakeup(dev))
713 		return -EINVAL;
714 
715 	handle = DEVICE_ACPI_HANDLE(dev);
716 	if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
717 		dev_dbg(dev, "ACPI handle has no context in %s!\n", __func__);
718 		return -ENODEV;
719 	}
720 
721 	error = enable ?
722 		acpi_enable_wakeup_device_power(adev, acpi_target_sleep_state) :
723 		acpi_disable_wakeup_device_power(adev);
724 	if (!error)
725 		dev_info(dev, "wake-up capability %s by ACPI\n",
726 				enable ? "enabled" : "disabled");
727 
728 	return error;
729 }
730 #endif  /* CONFIG_PM_SLEEP */
731 
732 static void acpi_power_off_prepare(void)
733 {
734 	/* Prepare to power off the system */
735 	acpi_sleep_prepare(ACPI_STATE_S5);
736 	acpi_disable_all_gpes();
737 }
738 
739 static void acpi_power_off(void)
740 {
741 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
742 	printk(KERN_DEBUG "%s called\n", __func__);
743 	local_irq_disable();
744 	acpi_enter_sleep_state(ACPI_STATE_S5);
745 }
746 
747 /*
748  * ACPI 2.0 created the optional _GTS and _BFS,
749  * but industry adoption has been neither rapid nor broad.
750  *
751  * Linux gets into trouble when it executes poorly validated
752  * paths through the BIOS, so disable _GTS and _BFS by default,
753  * but do speak up and offer the option to enable them.
754  */
755 static void __init acpi_gts_bfs_check(void)
756 {
757 	acpi_handle dummy;
758 
759 	if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__GTS, &dummy)))
760 	{
761 		printk(KERN_NOTICE PREFIX "BIOS offers _GTS\n");
762 		printk(KERN_NOTICE PREFIX "If \"acpi.gts=1\" improves suspend, "
763 			"please notify linux-acpi@vger.kernel.org\n");
764 	}
765 	if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__BFS, &dummy)))
766 	{
767 		printk(KERN_NOTICE PREFIX "BIOS offers _BFS\n");
768 		printk(KERN_NOTICE PREFIX "If \"acpi.bfs=1\" improves resume, "
769 			"please notify linux-acpi@vger.kernel.org\n");
770 	}
771 }
772 
773 int __init acpi_sleep_init(void)
774 {
775 	acpi_status status;
776 	u8 type_a, type_b;
777 #ifdef CONFIG_SUSPEND
778 	int i = 0;
779 
780 	dmi_check_system(acpisleep_dmi_table);
781 #endif
782 
783 	if (acpi_disabled)
784 		return 0;
785 
786 	sleep_states[ACPI_STATE_S0] = 1;
787 	printk(KERN_INFO PREFIX "(supports S0");
788 
789 #ifdef CONFIG_SUSPEND
790 	for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++) {
791 		status = acpi_get_sleep_type_data(i, &type_a, &type_b);
792 		if (ACPI_SUCCESS(status)) {
793 			sleep_states[i] = 1;
794 			printk(" S%d", i);
795 		}
796 	}
797 
798 	suspend_set_ops(old_suspend_ordering ?
799 		&acpi_suspend_ops_old : &acpi_suspend_ops);
800 #endif
801 
802 #ifdef CONFIG_HIBERNATION
803 	status = acpi_get_sleep_type_data(ACPI_STATE_S4, &type_a, &type_b);
804 	if (ACPI_SUCCESS(status)) {
805 		hibernation_set_ops(old_suspend_ordering ?
806 			&acpi_hibernation_ops_old : &acpi_hibernation_ops);
807 		sleep_states[ACPI_STATE_S4] = 1;
808 		printk(" S4");
809 		if (!nosigcheck) {
810 			acpi_get_table(ACPI_SIG_FACS, 1,
811 				(struct acpi_table_header **)&facs);
812 			if (facs)
813 				s4_hardware_signature =
814 					facs->hardware_signature;
815 		}
816 	}
817 #endif
818 	status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
819 	if (ACPI_SUCCESS(status)) {
820 		sleep_states[ACPI_STATE_S5] = 1;
821 		printk(" S5");
822 		pm_power_off_prepare = acpi_power_off_prepare;
823 		pm_power_off = acpi_power_off;
824 	}
825 	printk(")\n");
826 	/*
827 	 * Register the tts_notifier to reboot notifier list so that the _TTS
828 	 * object can also be evaluated when the system enters S5.
829 	 */
830 	register_reboot_notifier(&tts_notifier);
831 	acpi_gts_bfs_check();
832 	return 0;
833 }
834