xref: /linux/drivers/acpi/sleep.c (revision 2dbc0838bcf24ca59cabc3130cf3b1d6809cdcd4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * sleep.c - ACPI sleep support.
4  *
5  * Copyright (c) 2005 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
6  * Copyright (c) 2004 David Shaohua Li <shaohua.li@intel.com>
7  * Copyright (c) 2000-2003 Patrick Mochel
8  * Copyright (c) 2003 Open Source Development Lab
9  */
10 
11 #include <linux/delay.h>
12 #include <linux/irq.h>
13 #include <linux/dmi.h>
14 #include <linux/device.h>
15 #include <linux/interrupt.h>
16 #include <linux/suspend.h>
17 #include <linux/reboot.h>
18 #include <linux/acpi.h>
19 #include <linux/module.h>
20 #include <linux/syscore_ops.h>
21 #include <asm/io.h>
22 #include <trace/events/power.h>
23 
24 #include "internal.h"
25 #include "sleep.h"
26 
27 /*
28  * Some HW-full platforms do not have _S5, so they may need
29  * to leverage efi power off for a shutdown.
30  */
31 bool acpi_no_s5;
32 static u8 sleep_states[ACPI_S_STATE_COUNT];
33 
34 static void acpi_sleep_tts_switch(u32 acpi_state)
35 {
36 	acpi_status status;
37 
38 	status = acpi_execute_simple_method(NULL, "\\_TTS", acpi_state);
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 		acpi_set_waking_vector(acpi_wakeup_address);
69 
70 	}
71 	ACPI_FLUSH_CPU_CACHE();
72 #endif
73 	printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
74 		acpi_state);
75 	acpi_enable_wakeup_devices(acpi_state);
76 	acpi_enter_sleep_state_prep(acpi_state);
77 	return 0;
78 }
79 
80 bool acpi_sleep_state_supported(u8 sleep_state)
81 {
82 	acpi_status status;
83 	u8 type_a, type_b;
84 
85 	status = acpi_get_sleep_type_data(sleep_state, &type_a, &type_b);
86 	return ACPI_SUCCESS(status) && (!acpi_gbl_reduced_hardware
87 		|| (acpi_gbl_FADT.sleep_control.address
88 			&& acpi_gbl_FADT.sleep_status.address));
89 }
90 
91 #ifdef CONFIG_ACPI_SLEEP
92 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
93 
94 u32 acpi_target_system_state(void)
95 {
96 	return acpi_target_sleep_state;
97 }
98 EXPORT_SYMBOL_GPL(acpi_target_system_state);
99 
100 static bool pwr_btn_event_pending;
101 
102 /*
103  * The ACPI specification wants us to save NVS memory regions during hibernation
104  * and to restore them during the subsequent resume.  Windows does that also for
105  * suspend to RAM.  However, it is known that this mechanism does not work on
106  * all machines, so we allow the user to disable it with the help of the
107  * 'acpi_sleep=nonvs' kernel command line option.
108  */
109 static bool nvs_nosave;
110 
111 void __init acpi_nvs_nosave(void)
112 {
113 	nvs_nosave = true;
114 }
115 
116 /*
117  * The ACPI specification wants us to save NVS memory regions during hibernation
118  * but says nothing about saving NVS during S3.  Not all versions of Windows
119  * save NVS on S3 suspend either, and it is clear that not all systems need
120  * NVS to be saved at S3 time.  To improve suspend/resume time, allow the
121  * user to disable saving NVS on S3 if their system does not require it, but
122  * continue to save/restore NVS for S4 as specified.
123  */
124 static bool nvs_nosave_s3;
125 
126 void __init acpi_nvs_nosave_s3(void)
127 {
128 	nvs_nosave_s3 = true;
129 }
130 
131 static int __init init_nvs_save_s3(const struct dmi_system_id *d)
132 {
133 	nvs_nosave_s3 = false;
134 	return 0;
135 }
136 
137 /*
138  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
139  * user to request that behavior by using the 'acpi_old_suspend_ordering'
140  * kernel command line option that causes the following variable to be set.
141  */
142 static bool old_suspend_ordering;
143 
144 void __init acpi_old_suspend_ordering(void)
145 {
146 	old_suspend_ordering = true;
147 }
148 
149 static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
150 {
151 	acpi_old_suspend_ordering();
152 	return 0;
153 }
154 
155 static int __init init_nvs_nosave(const struct dmi_system_id *d)
156 {
157 	acpi_nvs_nosave();
158 	return 0;
159 }
160 
161 static bool acpi_sleep_no_lps0;
162 
163 static int __init init_no_lps0(const struct dmi_system_id *d)
164 {
165 	acpi_sleep_no_lps0 = true;
166 	return 0;
167 }
168 
169 static const struct dmi_system_id acpisleep_dmi_table[] __initconst = {
170 	{
171 	.callback = init_old_suspend_ordering,
172 	.ident = "Abit KN9 (nForce4 variant)",
173 	.matches = {
174 		DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
175 		DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
176 		},
177 	},
178 	{
179 	.callback = init_old_suspend_ordering,
180 	.ident = "HP xw4600 Workstation",
181 	.matches = {
182 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
183 		DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
184 		},
185 	},
186 	{
187 	.callback = init_old_suspend_ordering,
188 	.ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
189 	.matches = {
190 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTek Computer INC."),
191 		DMI_MATCH(DMI_BOARD_NAME, "M2N8L"),
192 		},
193 	},
194 	{
195 	.callback = init_old_suspend_ordering,
196 	.ident = "Panasonic CF51-2L",
197 	.matches = {
198 		DMI_MATCH(DMI_BOARD_VENDOR,
199 				"Matsushita Electric Industrial Co.,Ltd."),
200 		DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
201 		},
202 	},
203 	{
204 	.callback = init_nvs_nosave,
205 	.ident = "Sony Vaio VGN-FW41E_H",
206 	.matches = {
207 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
208 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW41E_H"),
209 		},
210 	},
211 	{
212 	.callback = init_nvs_nosave,
213 	.ident = "Sony Vaio VGN-FW21E",
214 	.matches = {
215 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
216 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21E"),
217 		},
218 	},
219 	{
220 	.callback = init_nvs_nosave,
221 	.ident = "Sony Vaio VGN-FW21M",
222 	.matches = {
223 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
224 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21M"),
225 		},
226 	},
227 	{
228 	.callback = init_nvs_nosave,
229 	.ident = "Sony Vaio VPCEB17FX",
230 	.matches = {
231 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
232 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB17FX"),
233 		},
234 	},
235 	{
236 	.callback = init_nvs_nosave,
237 	.ident = "Sony Vaio VGN-SR11M",
238 	.matches = {
239 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
240 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR11M"),
241 		},
242 	},
243 	{
244 	.callback = init_nvs_nosave,
245 	.ident = "Everex StepNote Series",
246 	.matches = {
247 		DMI_MATCH(DMI_SYS_VENDOR, "Everex Systems, Inc."),
248 		DMI_MATCH(DMI_PRODUCT_NAME, "Everex StepNote Series"),
249 		},
250 	},
251 	{
252 	.callback = init_nvs_nosave,
253 	.ident = "Sony Vaio VPCEB1Z1E",
254 	.matches = {
255 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
256 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1Z1E"),
257 		},
258 	},
259 	{
260 	.callback = init_nvs_nosave,
261 	.ident = "Sony Vaio VGN-NW130D",
262 	.matches = {
263 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
264 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-NW130D"),
265 		},
266 	},
267 	{
268 	.callback = init_nvs_nosave,
269 	.ident = "Sony Vaio VPCCW29FX",
270 	.matches = {
271 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
272 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCCW29FX"),
273 		},
274 	},
275 	{
276 	.callback = init_nvs_nosave,
277 	.ident = "Averatec AV1020-ED2",
278 	.matches = {
279 		DMI_MATCH(DMI_SYS_VENDOR, "AVERATEC"),
280 		DMI_MATCH(DMI_PRODUCT_NAME, "1000 Series"),
281 		},
282 	},
283 	{
284 	.callback = init_old_suspend_ordering,
285 	.ident = "Asus A8N-SLI DELUXE",
286 	.matches = {
287 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
288 		DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI DELUXE"),
289 		},
290 	},
291 	{
292 	.callback = init_old_suspend_ordering,
293 	.ident = "Asus A8N-SLI Premium",
294 	.matches = {
295 		DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
296 		DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI Premium"),
297 		},
298 	},
299 	{
300 	.callback = init_nvs_nosave,
301 	.ident = "Sony Vaio VGN-SR26GN_P",
302 	.matches = {
303 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
304 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR26GN_P"),
305 		},
306 	},
307 	{
308 	.callback = init_nvs_nosave,
309 	.ident = "Sony Vaio VPCEB1S1E",
310 	.matches = {
311 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
312 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1S1E"),
313 		},
314 	},
315 	{
316 	.callback = init_nvs_nosave,
317 	.ident = "Sony Vaio VGN-FW520F",
318 	.matches = {
319 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
320 		DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW520F"),
321 		},
322 	},
323 	{
324 	.callback = init_nvs_nosave,
325 	.ident = "Asus K54C",
326 	.matches = {
327 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
328 		DMI_MATCH(DMI_PRODUCT_NAME, "K54C"),
329 		},
330 	},
331 	{
332 	.callback = init_nvs_nosave,
333 	.ident = "Asus K54HR",
334 	.matches = {
335 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
336 		DMI_MATCH(DMI_PRODUCT_NAME, "K54HR"),
337 		},
338 	},
339 	{
340 	.callback = init_nvs_save_s3,
341 	.ident = "Asus 1025C",
342 	.matches = {
343 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
344 		DMI_MATCH(DMI_PRODUCT_NAME, "1025C"),
345 		},
346 	},
347 	/*
348 	 * https://bugzilla.kernel.org/show_bug.cgi?id=189431
349 	 * Lenovo G50-45 is a platform later than 2012, but needs nvs memory
350 	 * saving during S3.
351 	 */
352 	{
353 	.callback = init_nvs_save_s3,
354 	.ident = "Lenovo G50-45",
355 	.matches = {
356 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
357 		DMI_MATCH(DMI_PRODUCT_NAME, "80E3"),
358 		},
359 	},
360 	/*
361 	 * https://bugzilla.kernel.org/show_bug.cgi?id=196907
362 	 * Some Dell XPS13 9360 cannot do suspend-to-idle using the Low Power
363 	 * S0 Idle firmware interface.
364 	 */
365 	{
366 	.callback = init_no_lps0,
367 	.ident = "Dell XPS13 9360",
368 	.matches = {
369 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
370 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS 13 9360"),
371 		},
372 	},
373 	/*
374 	 * ThinkPad X1 Tablet(2016) cannot do suspend-to-idle using
375 	 * the Low Power S0 Idle firmware interface (see
376 	 * https://bugzilla.kernel.org/show_bug.cgi?id=199057).
377 	 */
378 	{
379 	.callback = init_no_lps0,
380 	.ident = "ThinkPad X1 Tablet(2016)",
381 	.matches = {
382 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
383 		DMI_MATCH(DMI_PRODUCT_NAME, "20GGA00L00"),
384 		},
385 	},
386 	{},
387 };
388 
389 static bool ignore_blacklist;
390 
391 void __init acpi_sleep_no_blacklist(void)
392 {
393 	ignore_blacklist = true;
394 }
395 
396 static void __init acpi_sleep_dmi_check(void)
397 {
398 	if (ignore_blacklist)
399 		return;
400 
401 	if (dmi_get_bios_year() >= 2012)
402 		acpi_nvs_nosave_s3();
403 
404 	dmi_check_system(acpisleep_dmi_table);
405 }
406 
407 /**
408  * acpi_pm_freeze - Disable the GPEs and suspend EC transactions.
409  */
410 static int acpi_pm_freeze(void)
411 {
412 	acpi_disable_all_gpes();
413 	acpi_os_wait_events_complete();
414 	acpi_ec_block_transactions();
415 	return 0;
416 }
417 
418 /**
419  * acpi_pre_suspend - Enable wakeup devices, "freeze" EC and save NVS.
420  */
421 static int acpi_pm_pre_suspend(void)
422 {
423 	acpi_pm_freeze();
424 	return suspend_nvs_save();
425 }
426 
427 /**
428  *	__acpi_pm_prepare - Prepare the platform to enter the target state.
429  *
430  *	If necessary, set the firmware waking vector and do arch-specific
431  *	nastiness to get the wakeup code to the waking vector.
432  */
433 static int __acpi_pm_prepare(void)
434 {
435 	int error = acpi_sleep_prepare(acpi_target_sleep_state);
436 	if (error)
437 		acpi_target_sleep_state = ACPI_STATE_S0;
438 
439 	return error;
440 }
441 
442 /**
443  *	acpi_pm_prepare - Prepare the platform to enter the target sleep
444  *		state and disable the GPEs.
445  */
446 static int acpi_pm_prepare(void)
447 {
448 	int error = __acpi_pm_prepare();
449 	if (!error)
450 		error = acpi_pm_pre_suspend();
451 
452 	return error;
453 }
454 
455 /**
456  *	acpi_pm_finish - Instruct the platform to leave a sleep state.
457  *
458  *	This is called after we wake back up (or if entering the sleep state
459  *	failed).
460  */
461 static void acpi_pm_finish(void)
462 {
463 	struct acpi_device *pwr_btn_adev;
464 	u32 acpi_state = acpi_target_sleep_state;
465 
466 	acpi_ec_unblock_transactions();
467 	suspend_nvs_free();
468 
469 	if (acpi_state == ACPI_STATE_S0)
470 		return;
471 
472 	printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
473 		acpi_state);
474 	acpi_disable_wakeup_devices(acpi_state);
475 	acpi_leave_sleep_state(acpi_state);
476 
477 	/* reset firmware waking vector */
478 	acpi_set_waking_vector(0);
479 
480 	acpi_target_sleep_state = ACPI_STATE_S0;
481 
482 	acpi_resume_power_resources();
483 
484 	/* If we were woken with the fixed power button, provide a small
485 	 * hint to userspace in the form of a wakeup event on the fixed power
486 	 * button device (if it can be found).
487 	 *
488 	 * We delay the event generation til now, as the PM layer requires
489 	 * timekeeping to be running before we generate events. */
490 	if (!pwr_btn_event_pending)
491 		return;
492 
493 	pwr_btn_event_pending = false;
494 	pwr_btn_adev = acpi_dev_get_first_match_dev(ACPI_BUTTON_HID_POWERF,
495 						    NULL, -1);
496 	if (pwr_btn_adev) {
497 		pm_wakeup_event(&pwr_btn_adev->dev, 0);
498 		acpi_dev_put(pwr_btn_adev);
499 	}
500 }
501 
502 /**
503  * acpi_pm_start - Start system PM transition.
504  */
505 static void acpi_pm_start(u32 acpi_state)
506 {
507 	acpi_target_sleep_state = acpi_state;
508 	acpi_sleep_tts_switch(acpi_target_sleep_state);
509 	acpi_scan_lock_acquire();
510 }
511 
512 /**
513  * acpi_pm_end - Finish up system PM transition.
514  */
515 static void acpi_pm_end(void)
516 {
517 	acpi_turn_off_unused_power_resources();
518 	acpi_scan_lock_release();
519 	/*
520 	 * This is necessary in case acpi_pm_finish() is not called during a
521 	 * failing transition to a sleep state.
522 	 */
523 	acpi_target_sleep_state = ACPI_STATE_S0;
524 	acpi_sleep_tts_switch(acpi_target_sleep_state);
525 }
526 #else /* !CONFIG_ACPI_SLEEP */
527 #define acpi_target_sleep_state	ACPI_STATE_S0
528 #define acpi_sleep_no_lps0	(false)
529 static inline void acpi_sleep_dmi_check(void) {}
530 #endif /* CONFIG_ACPI_SLEEP */
531 
532 #ifdef CONFIG_SUSPEND
533 static u32 acpi_suspend_states[] = {
534 	[PM_SUSPEND_ON] = ACPI_STATE_S0,
535 	[PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
536 	[PM_SUSPEND_MEM] = ACPI_STATE_S3,
537 	[PM_SUSPEND_MAX] = ACPI_STATE_S5
538 };
539 
540 /**
541  *	acpi_suspend_begin - Set the target system sleep state to the state
542  *		associated with given @pm_state, if supported.
543  */
544 static int acpi_suspend_begin(suspend_state_t pm_state)
545 {
546 	u32 acpi_state = acpi_suspend_states[pm_state];
547 	int error;
548 
549 	error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();
550 	if (error)
551 		return error;
552 
553 	if (!sleep_states[acpi_state]) {
554 		pr_err("ACPI does not support sleep state S%u\n", acpi_state);
555 		return -ENOSYS;
556 	}
557 	if (acpi_state > ACPI_STATE_S1)
558 		pm_set_suspend_via_firmware();
559 
560 	acpi_pm_start(acpi_state);
561 	return 0;
562 }
563 
564 /**
565  *	acpi_suspend_enter - Actually enter a sleep state.
566  *	@pm_state: ignored
567  *
568  *	Flush caches and go to sleep. For STR we have to call arch-specific
569  *	assembly, which in turn call acpi_enter_sleep_state().
570  *	It's unfortunate, but it works. Please fix if you're feeling frisky.
571  */
572 static int acpi_suspend_enter(suspend_state_t pm_state)
573 {
574 	acpi_status status = AE_OK;
575 	u32 acpi_state = acpi_target_sleep_state;
576 	int error;
577 
578 	ACPI_FLUSH_CPU_CACHE();
579 
580 	trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true);
581 	switch (acpi_state) {
582 	case ACPI_STATE_S1:
583 		barrier();
584 		status = acpi_enter_sleep_state(acpi_state);
585 		break;
586 
587 	case ACPI_STATE_S3:
588 		if (!acpi_suspend_lowlevel)
589 			return -ENOSYS;
590 		error = acpi_suspend_lowlevel();
591 		if (error)
592 			return error;
593 		pr_info(PREFIX "Low-level resume complete\n");
594 		pm_set_resume_via_firmware();
595 		break;
596 	}
597 	trace_suspend_resume(TPS("acpi_suspend"), acpi_state, false);
598 
599 	/* This violates the spec but is required for bug compatibility. */
600 	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
601 
602 	/* Reprogram control registers */
603 	acpi_leave_sleep_state_prep(acpi_state);
604 
605 	/* ACPI 3.0 specs (P62) says that it's the responsibility
606 	 * of the OSPM to clear the status bit [ implying that the
607 	 * POWER_BUTTON event should not reach userspace ]
608 	 *
609 	 * However, we do generate a small hint for userspace in the form of
610 	 * a wakeup event. We flag this condition for now and generate the
611 	 * event later, as we're currently too early in resume to be able to
612 	 * generate wakeup events.
613 	 */
614 	if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
615 		acpi_event_status pwr_btn_status = ACPI_EVENT_FLAG_DISABLED;
616 
617 		acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);
618 
619 		if (pwr_btn_status & ACPI_EVENT_FLAG_STATUS_SET) {
620 			acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
621 			/* Flag for later */
622 			pwr_btn_event_pending = true;
623 		}
624 	}
625 
626 	/*
627 	 * Disable and clear GPE status before interrupt is enabled. Some GPEs
628 	 * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
629 	 * acpi_leave_sleep_state will reenable specific GPEs later
630 	 */
631 	acpi_disable_all_gpes();
632 	/* Allow EC transactions to happen. */
633 	acpi_ec_unblock_transactions();
634 
635 	suspend_nvs_restore();
636 
637 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
638 }
639 
640 static int acpi_suspend_state_valid(suspend_state_t pm_state)
641 {
642 	u32 acpi_state;
643 
644 	switch (pm_state) {
645 	case PM_SUSPEND_ON:
646 	case PM_SUSPEND_STANDBY:
647 	case PM_SUSPEND_MEM:
648 		acpi_state = acpi_suspend_states[pm_state];
649 
650 		return sleep_states[acpi_state];
651 	default:
652 		return 0;
653 	}
654 }
655 
656 static const struct platform_suspend_ops acpi_suspend_ops = {
657 	.valid = acpi_suspend_state_valid,
658 	.begin = acpi_suspend_begin,
659 	.prepare_late = acpi_pm_prepare,
660 	.enter = acpi_suspend_enter,
661 	.wake = acpi_pm_finish,
662 	.end = acpi_pm_end,
663 };
664 
665 /**
666  *	acpi_suspend_begin_old - Set the target system sleep state to the
667  *		state associated with given @pm_state, if supported, and
668  *		execute the _PTS control method.  This function is used if the
669  *		pre-ACPI 2.0 suspend ordering has been requested.
670  */
671 static int acpi_suspend_begin_old(suspend_state_t pm_state)
672 {
673 	int error = acpi_suspend_begin(pm_state);
674 	if (!error)
675 		error = __acpi_pm_prepare();
676 
677 	return error;
678 }
679 
680 /*
681  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
682  * been requested.
683  */
684 static const struct platform_suspend_ops acpi_suspend_ops_old = {
685 	.valid = acpi_suspend_state_valid,
686 	.begin = acpi_suspend_begin_old,
687 	.prepare_late = acpi_pm_pre_suspend,
688 	.enter = acpi_suspend_enter,
689 	.wake = acpi_pm_finish,
690 	.end = acpi_pm_end,
691 	.recover = acpi_pm_finish,
692 };
693 
694 static bool s2idle_in_progress;
695 static bool s2idle_wakeup;
696 
697 /*
698  * On platforms supporting the Low Power S0 Idle interface there is an ACPI
699  * device object with the PNP0D80 compatible device ID (System Power Management
700  * Controller) and a specific _DSM method under it.  That method, if present,
701  * can be used to indicate to the platform that the OS is transitioning into a
702  * low-power state in which certain types of activity are not desirable or that
703  * it is leaving such a state, which allows the platform to adjust its operation
704  * mode accordingly.
705  */
706 static const struct acpi_device_id lps0_device_ids[] = {
707 	{"PNP0D80", },
708 	{"", },
709 };
710 
711 #define ACPI_LPS0_DSM_UUID	"c4eb40a0-6cd2-11e2-bcfd-0800200c9a66"
712 
713 #define ACPI_LPS0_GET_DEVICE_CONSTRAINTS	1
714 #define ACPI_LPS0_SCREEN_OFF	3
715 #define ACPI_LPS0_SCREEN_ON	4
716 #define ACPI_LPS0_ENTRY		5
717 #define ACPI_LPS0_EXIT		6
718 
719 static acpi_handle lps0_device_handle;
720 static guid_t lps0_dsm_guid;
721 static char lps0_dsm_func_mask;
722 
723 /* Device constraint entry structure */
724 struct lpi_device_info {
725 	char *name;
726 	int enabled;
727 	union acpi_object *package;
728 };
729 
730 /* Constraint package structure */
731 struct lpi_device_constraint {
732 	int uid;
733 	int min_dstate;
734 	int function_states;
735 };
736 
737 struct lpi_constraints {
738 	acpi_handle handle;
739 	int min_dstate;
740 };
741 
742 static struct lpi_constraints *lpi_constraints_table;
743 static int lpi_constraints_table_size;
744 
745 static void lpi_device_get_constraints(void)
746 {
747 	union acpi_object *out_obj;
748 	int i;
749 
750 	out_obj = acpi_evaluate_dsm_typed(lps0_device_handle, &lps0_dsm_guid,
751 					  1, ACPI_LPS0_GET_DEVICE_CONSTRAINTS,
752 					  NULL, ACPI_TYPE_PACKAGE);
753 
754 	acpi_handle_debug(lps0_device_handle, "_DSM function 1 eval %s\n",
755 			  out_obj ? "successful" : "failed");
756 
757 	if (!out_obj)
758 		return;
759 
760 	lpi_constraints_table = kcalloc(out_obj->package.count,
761 					sizeof(*lpi_constraints_table),
762 					GFP_KERNEL);
763 	if (!lpi_constraints_table)
764 		goto free_acpi_buffer;
765 
766 	acpi_handle_debug(lps0_device_handle, "LPI: constraints list begin:\n");
767 
768 	for (i = 0; i < out_obj->package.count; i++) {
769 		struct lpi_constraints *constraint;
770 		acpi_status status;
771 		union acpi_object *package = &out_obj->package.elements[i];
772 		struct lpi_device_info info = { };
773 		int package_count = 0, j;
774 
775 		if (!package)
776 			continue;
777 
778 		for (j = 0; j < package->package.count; ++j) {
779 			union acpi_object *element =
780 					&(package->package.elements[j]);
781 
782 			switch (element->type) {
783 			case ACPI_TYPE_INTEGER:
784 				info.enabled = element->integer.value;
785 				break;
786 			case ACPI_TYPE_STRING:
787 				info.name = element->string.pointer;
788 				break;
789 			case ACPI_TYPE_PACKAGE:
790 				package_count = element->package.count;
791 				info.package = element->package.elements;
792 				break;
793 			}
794 		}
795 
796 		if (!info.enabled || !info.package || !info.name)
797 			continue;
798 
799 		constraint = &lpi_constraints_table[lpi_constraints_table_size];
800 
801 		status = acpi_get_handle(NULL, info.name, &constraint->handle);
802 		if (ACPI_FAILURE(status))
803 			continue;
804 
805 		acpi_handle_debug(lps0_device_handle,
806 				  "index:%d Name:%s\n", i, info.name);
807 
808 		constraint->min_dstate = -1;
809 
810 		for (j = 0; j < package_count; ++j) {
811 			union acpi_object *info_obj = &info.package[j];
812 			union acpi_object *cnstr_pkg;
813 			union acpi_object *obj;
814 			struct lpi_device_constraint dev_info;
815 
816 			switch (info_obj->type) {
817 			case ACPI_TYPE_INTEGER:
818 				/* version */
819 				break;
820 			case ACPI_TYPE_PACKAGE:
821 				if (info_obj->package.count < 2)
822 					break;
823 
824 				cnstr_pkg = info_obj->package.elements;
825 				obj = &cnstr_pkg[0];
826 				dev_info.uid = obj->integer.value;
827 				obj = &cnstr_pkg[1];
828 				dev_info.min_dstate = obj->integer.value;
829 
830 				acpi_handle_debug(lps0_device_handle,
831 					"uid:%d min_dstate:%s\n",
832 					dev_info.uid,
833 					acpi_power_state_string(dev_info.min_dstate));
834 
835 				constraint->min_dstate = dev_info.min_dstate;
836 				break;
837 			}
838 		}
839 
840 		if (constraint->min_dstate < 0) {
841 			acpi_handle_debug(lps0_device_handle,
842 					  "Incomplete constraint defined\n");
843 			continue;
844 		}
845 
846 		lpi_constraints_table_size++;
847 	}
848 
849 	acpi_handle_debug(lps0_device_handle, "LPI: constraints list end\n");
850 
851 free_acpi_buffer:
852 	ACPI_FREE(out_obj);
853 }
854 
855 static void lpi_check_constraints(void)
856 {
857 	int i;
858 
859 	for (i = 0; i < lpi_constraints_table_size; ++i) {
860 		acpi_handle handle = lpi_constraints_table[i].handle;
861 		struct acpi_device *adev;
862 
863 		if (!handle || acpi_bus_get_device(handle, &adev))
864 			continue;
865 
866 		acpi_handle_debug(handle,
867 			"LPI: required min power state:%s current power state:%s\n",
868 			acpi_power_state_string(lpi_constraints_table[i].min_dstate),
869 			acpi_power_state_string(adev->power.state));
870 
871 		if (!adev->flags.power_manageable) {
872 			acpi_handle_info(handle, "LPI: Device not power manageable\n");
873 			lpi_constraints_table[i].handle = NULL;
874 			continue;
875 		}
876 
877 		if (adev->power.state < lpi_constraints_table[i].min_dstate)
878 			acpi_handle_info(handle,
879 				"LPI: Constraint not met; min power state:%s current power state:%s\n",
880 				acpi_power_state_string(lpi_constraints_table[i].min_dstate),
881 				acpi_power_state_string(adev->power.state));
882 	}
883 }
884 
885 static void acpi_sleep_run_lps0_dsm(unsigned int func)
886 {
887 	union acpi_object *out_obj;
888 
889 	if (!(lps0_dsm_func_mask & (1 << func)))
890 		return;
891 
892 	out_obj = acpi_evaluate_dsm(lps0_device_handle, &lps0_dsm_guid, 1, func, NULL);
893 	ACPI_FREE(out_obj);
894 
895 	acpi_handle_debug(lps0_device_handle, "_DSM function %u evaluation %s\n",
896 			  func, out_obj ? "successful" : "failed");
897 }
898 
899 static int lps0_device_attach(struct acpi_device *adev,
900 			      const struct acpi_device_id *not_used)
901 {
902 	union acpi_object *out_obj;
903 
904 	if (lps0_device_handle)
905 		return 0;
906 
907 	if (acpi_sleep_no_lps0) {
908 		acpi_handle_info(adev->handle,
909 				 "Low Power S0 Idle interface disabled\n");
910 		return 0;
911 	}
912 
913 	if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
914 		return 0;
915 
916 	guid_parse(ACPI_LPS0_DSM_UUID, &lps0_dsm_guid);
917 	/* Check if the _DSM is present and as expected. */
918 	out_obj = acpi_evaluate_dsm(adev->handle, &lps0_dsm_guid, 1, 0, NULL);
919 	if (out_obj && out_obj->type == ACPI_TYPE_BUFFER) {
920 		char bitmask = *(char *)out_obj->buffer.pointer;
921 
922 		lps0_dsm_func_mask = bitmask;
923 		lps0_device_handle = adev->handle;
924 		/*
925 		 * Use suspend-to-idle by default if the default
926 		 * suspend mode was not set from the command line.
927 		 */
928 		if (mem_sleep_default > PM_SUSPEND_MEM)
929 			mem_sleep_current = PM_SUSPEND_TO_IDLE;
930 
931 		acpi_handle_debug(adev->handle, "_DSM function mask: 0x%x\n",
932 				  bitmask);
933 
934 		acpi_ec_mark_gpe_for_wake();
935 	} else {
936 		acpi_handle_debug(adev->handle,
937 				  "_DSM function 0 evaluation failed\n");
938 	}
939 	ACPI_FREE(out_obj);
940 
941 	lpi_device_get_constraints();
942 
943 	return 0;
944 }
945 
946 static struct acpi_scan_handler lps0_handler = {
947 	.ids = lps0_device_ids,
948 	.attach = lps0_device_attach,
949 };
950 
951 static int acpi_s2idle_begin(void)
952 {
953 	acpi_scan_lock_acquire();
954 	s2idle_in_progress = true;
955 	return 0;
956 }
957 
958 static int acpi_s2idle_prepare(void)
959 {
960 	if (lps0_device_handle) {
961 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF);
962 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY);
963 
964 		acpi_ec_set_gpe_wake_mask(ACPI_GPE_ENABLE);
965 	}
966 
967 	if (acpi_sci_irq_valid())
968 		enable_irq_wake(acpi_sci_irq);
969 
970 	acpi_enable_wakeup_devices(ACPI_STATE_S0);
971 
972 	/* Change the configuration of GPEs to avoid spurious wakeup. */
973 	acpi_enable_all_wakeup_gpes();
974 	acpi_os_wait_events_complete();
975 	return 0;
976 }
977 
978 static void acpi_s2idle_wake(void)
979 {
980 	if (!lps0_device_handle)
981 		return;
982 
983 	if (pm_debug_messages_on)
984 		lpi_check_constraints();
985 
986 	/*
987 	 * If IRQD_WAKEUP_ARMED is not set for the SCI at this point, it means
988 	 * that the SCI has triggered while suspended, so cancel the wakeup in
989 	 * case it has not been a wakeup event (the GPEs will be checked later).
990 	 */
991 	if (acpi_sci_irq_valid() &&
992 	    !irqd_is_wakeup_armed(irq_get_irq_data(acpi_sci_irq))) {
993 		pm_system_cancel_wakeup();
994 		s2idle_wakeup = true;
995 		/*
996 		 * On some platforms with the LPS0 _DSM device noirq resume
997 		 * takes too much time for EC wakeup events to survive, so look
998 		 * for them now.
999 		 */
1000 		acpi_ec_dispatch_gpe();
1001 	}
1002 }
1003 
1004 static void acpi_s2idle_sync(void)
1005 {
1006 	/*
1007 	 * Process all pending events in case there are any wakeup ones.
1008 	 *
1009 	 * The EC driver uses the system workqueue and an additional special
1010 	 * one, so those need to be flushed too.
1011 	 */
1012 	acpi_os_wait_events_complete();	/* synchronize SCI IRQ handling */
1013 	acpi_ec_flush_work();
1014 	acpi_os_wait_events_complete();	/* synchronize Notify handling */
1015 	s2idle_wakeup = false;
1016 }
1017 
1018 static void acpi_s2idle_restore(void)
1019 {
1020 	acpi_enable_all_runtime_gpes();
1021 
1022 	acpi_disable_wakeup_devices(ACPI_STATE_S0);
1023 
1024 	if (acpi_sci_irq_valid())
1025 		disable_irq_wake(acpi_sci_irq);
1026 
1027 	if (lps0_device_handle) {
1028 		acpi_ec_set_gpe_wake_mask(ACPI_GPE_DISABLE);
1029 
1030 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT);
1031 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON);
1032 	}
1033 }
1034 
1035 static void acpi_s2idle_end(void)
1036 {
1037 	s2idle_in_progress = false;
1038 	acpi_scan_lock_release();
1039 }
1040 
1041 static const struct platform_s2idle_ops acpi_s2idle_ops = {
1042 	.begin = acpi_s2idle_begin,
1043 	.prepare = acpi_s2idle_prepare,
1044 	.wake = acpi_s2idle_wake,
1045 	.sync = acpi_s2idle_sync,
1046 	.restore = acpi_s2idle_restore,
1047 	.end = acpi_s2idle_end,
1048 };
1049 
1050 static void acpi_sleep_suspend_setup(void)
1051 {
1052 	int i;
1053 
1054 	for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++)
1055 		if (acpi_sleep_state_supported(i))
1056 			sleep_states[i] = 1;
1057 
1058 	suspend_set_ops(old_suspend_ordering ?
1059 		&acpi_suspend_ops_old : &acpi_suspend_ops);
1060 
1061 	acpi_scan_add_handler(&lps0_handler);
1062 	s2idle_set_ops(&acpi_s2idle_ops);
1063 }
1064 
1065 #else /* !CONFIG_SUSPEND */
1066 #define s2idle_in_progress	(false)
1067 #define s2idle_wakeup		(false)
1068 #define lps0_device_handle	(NULL)
1069 static inline void acpi_sleep_suspend_setup(void) {}
1070 #endif /* !CONFIG_SUSPEND */
1071 
1072 bool acpi_s2idle_wakeup(void)
1073 {
1074 	return s2idle_wakeup;
1075 }
1076 
1077 bool acpi_sleep_no_ec_events(void)
1078 {
1079 	return !s2idle_in_progress || !lps0_device_handle;
1080 }
1081 
1082 #ifdef CONFIG_PM_SLEEP
1083 static u32 saved_bm_rld;
1084 
1085 static int  acpi_save_bm_rld(void)
1086 {
1087 	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
1088 	return 0;
1089 }
1090 
1091 static void  acpi_restore_bm_rld(void)
1092 {
1093 	u32 resumed_bm_rld = 0;
1094 
1095 	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
1096 	if (resumed_bm_rld == saved_bm_rld)
1097 		return;
1098 
1099 	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
1100 }
1101 
1102 static struct syscore_ops acpi_sleep_syscore_ops = {
1103 	.suspend = acpi_save_bm_rld,
1104 	.resume = acpi_restore_bm_rld,
1105 };
1106 
1107 static void acpi_sleep_syscore_init(void)
1108 {
1109 	register_syscore_ops(&acpi_sleep_syscore_ops);
1110 }
1111 #else
1112 static inline void acpi_sleep_syscore_init(void) {}
1113 #endif /* CONFIG_PM_SLEEP */
1114 
1115 #ifdef CONFIG_HIBERNATION
1116 static unsigned long s4_hardware_signature;
1117 static struct acpi_table_facs *facs;
1118 static bool nosigcheck;
1119 
1120 void __init acpi_no_s4_hw_signature(void)
1121 {
1122 	nosigcheck = true;
1123 }
1124 
1125 static int acpi_hibernation_begin(pm_message_t stage)
1126 {
1127 	if (!nvs_nosave) {
1128 		int error = suspend_nvs_alloc();
1129 		if (error)
1130 			return error;
1131 	}
1132 
1133 	if (stage.event == PM_EVENT_HIBERNATE)
1134 		pm_set_suspend_via_firmware();
1135 
1136 	acpi_pm_start(ACPI_STATE_S4);
1137 	return 0;
1138 }
1139 
1140 static int acpi_hibernation_enter(void)
1141 {
1142 	acpi_status status = AE_OK;
1143 
1144 	ACPI_FLUSH_CPU_CACHE();
1145 
1146 	/* This shouldn't return.  If it returns, we have a problem */
1147 	status = acpi_enter_sleep_state(ACPI_STATE_S4);
1148 	/* Reprogram control registers */
1149 	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
1150 
1151 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
1152 }
1153 
1154 static void acpi_hibernation_leave(void)
1155 {
1156 	pm_set_resume_via_firmware();
1157 	/*
1158 	 * If ACPI is not enabled by the BIOS and the boot kernel, we need to
1159 	 * enable it here.
1160 	 */
1161 	acpi_enable();
1162 	/* Reprogram control registers */
1163 	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
1164 	/* Check the hardware signature */
1165 	if (facs && s4_hardware_signature != facs->hardware_signature)
1166 		pr_crit("ACPI: Hardware changed while hibernated, success doubtful!\n");
1167 	/* Restore the NVS memory area */
1168 	suspend_nvs_restore();
1169 	/* Allow EC transactions to happen. */
1170 	acpi_ec_unblock_transactions();
1171 }
1172 
1173 static void acpi_pm_thaw(void)
1174 {
1175 	acpi_ec_unblock_transactions();
1176 	acpi_enable_all_runtime_gpes();
1177 }
1178 
1179 static const struct platform_hibernation_ops acpi_hibernation_ops = {
1180 	.begin = acpi_hibernation_begin,
1181 	.end = acpi_pm_end,
1182 	.pre_snapshot = acpi_pm_prepare,
1183 	.finish = acpi_pm_finish,
1184 	.prepare = acpi_pm_prepare,
1185 	.enter = acpi_hibernation_enter,
1186 	.leave = acpi_hibernation_leave,
1187 	.pre_restore = acpi_pm_freeze,
1188 	.restore_cleanup = acpi_pm_thaw,
1189 };
1190 
1191 /**
1192  *	acpi_hibernation_begin_old - Set the target system sleep state to
1193  *		ACPI_STATE_S4 and execute the _PTS control method.  This
1194  *		function is used if the pre-ACPI 2.0 suspend ordering has been
1195  *		requested.
1196  */
1197 static int acpi_hibernation_begin_old(pm_message_t stage)
1198 {
1199 	int error;
1200 	/*
1201 	 * The _TTS object should always be evaluated before the _PTS object.
1202 	 * When the old_suspended_ordering is true, the _PTS object is
1203 	 * evaluated in the acpi_sleep_prepare.
1204 	 */
1205 	acpi_sleep_tts_switch(ACPI_STATE_S4);
1206 
1207 	error = acpi_sleep_prepare(ACPI_STATE_S4);
1208 	if (error)
1209 		return error;
1210 
1211 	if (!nvs_nosave) {
1212 		error = suspend_nvs_alloc();
1213 		if (error)
1214 			return error;
1215 	}
1216 
1217 	if (stage.event == PM_EVENT_HIBERNATE)
1218 		pm_set_suspend_via_firmware();
1219 
1220 	acpi_target_sleep_state = ACPI_STATE_S4;
1221 	acpi_scan_lock_acquire();
1222 	return 0;
1223 }
1224 
1225 /*
1226  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
1227  * been requested.
1228  */
1229 static const struct platform_hibernation_ops acpi_hibernation_ops_old = {
1230 	.begin = acpi_hibernation_begin_old,
1231 	.end = acpi_pm_end,
1232 	.pre_snapshot = acpi_pm_pre_suspend,
1233 	.prepare = acpi_pm_freeze,
1234 	.finish = acpi_pm_finish,
1235 	.enter = acpi_hibernation_enter,
1236 	.leave = acpi_hibernation_leave,
1237 	.pre_restore = acpi_pm_freeze,
1238 	.restore_cleanup = acpi_pm_thaw,
1239 	.recover = acpi_pm_finish,
1240 };
1241 
1242 static void acpi_sleep_hibernate_setup(void)
1243 {
1244 	if (!acpi_sleep_state_supported(ACPI_STATE_S4))
1245 		return;
1246 
1247 	hibernation_set_ops(old_suspend_ordering ?
1248 			&acpi_hibernation_ops_old : &acpi_hibernation_ops);
1249 	sleep_states[ACPI_STATE_S4] = 1;
1250 	if (nosigcheck)
1251 		return;
1252 
1253 	acpi_get_table(ACPI_SIG_FACS, 1, (struct acpi_table_header **)&facs);
1254 	if (facs)
1255 		s4_hardware_signature = facs->hardware_signature;
1256 }
1257 #else /* !CONFIG_HIBERNATION */
1258 static inline void acpi_sleep_hibernate_setup(void) {}
1259 #endif /* !CONFIG_HIBERNATION */
1260 
1261 static void acpi_power_off_prepare(void)
1262 {
1263 	/* Prepare to power off the system */
1264 	acpi_sleep_prepare(ACPI_STATE_S5);
1265 	acpi_disable_all_gpes();
1266 	acpi_os_wait_events_complete();
1267 }
1268 
1269 static void acpi_power_off(void)
1270 {
1271 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
1272 	printk(KERN_DEBUG "%s called\n", __func__);
1273 	local_irq_disable();
1274 	acpi_enter_sleep_state(ACPI_STATE_S5);
1275 }
1276 
1277 int __init acpi_sleep_init(void)
1278 {
1279 	char supported[ACPI_S_STATE_COUNT * 3 + 1];
1280 	char *pos = supported;
1281 	int i;
1282 
1283 	acpi_sleep_dmi_check();
1284 
1285 	sleep_states[ACPI_STATE_S0] = 1;
1286 
1287 	acpi_sleep_syscore_init();
1288 	acpi_sleep_suspend_setup();
1289 	acpi_sleep_hibernate_setup();
1290 
1291 	if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
1292 		sleep_states[ACPI_STATE_S5] = 1;
1293 		pm_power_off_prepare = acpi_power_off_prepare;
1294 		pm_power_off = acpi_power_off;
1295 	} else {
1296 		acpi_no_s5 = true;
1297 	}
1298 
1299 	supported[0] = 0;
1300 	for (i = 0; i < ACPI_S_STATE_COUNT; i++) {
1301 		if (sleep_states[i])
1302 			pos += sprintf(pos, " S%d", i);
1303 	}
1304 	pr_info(PREFIX "(supports%s)\n", supported);
1305 
1306 	/*
1307 	 * Register the tts_notifier to reboot notifier list so that the _TTS
1308 	 * object can also be evaluated when the system enters S5.
1309 	 */
1310 	register_reboot_notifier(&tts_notifier);
1311 	return 0;
1312 }
1313