2 * sleep.c - ACPI sleep support.
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
9 * This file is released under the GPLv2.
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 #include <linux/module.h>
22 #include <trace/events/power.h>
27 static u8 sleep_states[ACPI_S_STATE_COUNT];
29 static void acpi_sleep_tts_switch(u32 acpi_state)
33 status = acpi_execute_simple_method(NULL, "\\_TTS", acpi_state);
34 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
36 * OS can't evaluate the _TTS object correctly. Some warning
37 * message will be printed. But it won't break anything.
39 printk(KERN_NOTICE "Failure in evaluating _TTS object\n");
43 static int tts_notify_reboot(struct notifier_block *this,
44 unsigned long code, void *x)
46 acpi_sleep_tts_switch(ACPI_STATE_S5);
50 static struct notifier_block tts_notifier = {
51 .notifier_call = tts_notify_reboot,
56 static int acpi_sleep_prepare(u32 acpi_state)
58 #ifdef CONFIG_ACPI_SLEEP
59 /* do we have a wakeup address for S2 and S3? */
60 if (acpi_state == ACPI_STATE_S3) {
61 if (!acpi_wakeup_address)
63 acpi_set_firmware_waking_vector(acpi_wakeup_address);
66 ACPI_FLUSH_CPU_CACHE();
68 printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
70 acpi_enable_wakeup_devices(acpi_state);
71 acpi_enter_sleep_state_prep(acpi_state);
75 static bool acpi_sleep_state_supported(u8 sleep_state)
80 status = acpi_get_sleep_type_data(sleep_state, &type_a, &type_b);
81 return ACPI_SUCCESS(status) && (!acpi_gbl_reduced_hardware
82 || (acpi_gbl_FADT.sleep_control.address
83 && acpi_gbl_FADT.sleep_status.address));
86 #ifdef CONFIG_ACPI_SLEEP
87 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
89 u32 acpi_target_system_state(void)
91 return acpi_target_sleep_state;
93 EXPORT_SYMBOL_GPL(acpi_target_system_state);
95 static bool pwr_btn_event_pending;
98 * The ACPI specification wants us to save NVS memory regions during hibernation
99 * and to restore them during the subsequent resume. Windows does that also for
100 * suspend to RAM. However, it is known that this mechanism does not work on
101 * all machines, so we allow the user to disable it with the help of the
102 * 'acpi_sleep=nonvs' kernel command line option.
104 static bool nvs_nosave;
106 void __init acpi_nvs_nosave(void)
112 * The ACPI specification wants us to save NVS memory regions during hibernation
113 * but says nothing about saving NVS during S3. Not all versions of Windows
114 * save NVS on S3 suspend either, and it is clear that not all systems need
115 * NVS to be saved at S3 time. To improve suspend/resume time, allow the
116 * user to disable saving NVS on S3 if their system does not require it, but
117 * continue to save/restore NVS for S4 as specified.
119 static bool nvs_nosave_s3;
121 void __init acpi_nvs_nosave_s3(void)
123 nvs_nosave_s3 = true;
127 * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
128 * user to request that behavior by using the 'acpi_old_suspend_ordering'
129 * kernel command line option that causes the following variable to be set.
131 static bool old_suspend_ordering;
133 void __init acpi_old_suspend_ordering(void)
135 old_suspend_ordering = true;
138 static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
140 acpi_old_suspend_ordering();
144 static int __init init_nvs_nosave(const struct dmi_system_id *d)
150 static struct dmi_system_id acpisleep_dmi_table[] __initdata = {
152 .callback = init_old_suspend_ordering,
153 .ident = "Abit KN9 (nForce4 variant)",
155 DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
156 DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
160 .callback = init_old_suspend_ordering,
161 .ident = "HP xw4600 Workstation",
163 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
164 DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
168 .callback = init_old_suspend_ordering,
169 .ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
171 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTek Computer INC."),
172 DMI_MATCH(DMI_BOARD_NAME, "M2N8L"),
176 .callback = init_old_suspend_ordering,
177 .ident = "Panasonic CF51-2L",
179 DMI_MATCH(DMI_BOARD_VENDOR,
180 "Matsushita Electric Industrial Co.,Ltd."),
181 DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
185 .callback = init_nvs_nosave,
186 .ident = "Sony Vaio VGN-FW41E_H",
188 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
189 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW41E_H"),
193 .callback = init_nvs_nosave,
194 .ident = "Sony Vaio VGN-FW21E",
196 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
197 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21E"),
201 .callback = init_nvs_nosave,
202 .ident = "Sony Vaio VGN-FW21M",
204 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
205 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21M"),
209 .callback = init_nvs_nosave,
210 .ident = "Sony Vaio VPCEB17FX",
212 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
213 DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB17FX"),
217 .callback = init_nvs_nosave,
218 .ident = "Sony Vaio VGN-SR11M",
220 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
221 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR11M"),
225 .callback = init_nvs_nosave,
226 .ident = "Everex StepNote Series",
228 DMI_MATCH(DMI_SYS_VENDOR, "Everex Systems, Inc."),
229 DMI_MATCH(DMI_PRODUCT_NAME, "Everex StepNote Series"),
233 .callback = init_nvs_nosave,
234 .ident = "Sony Vaio VPCEB1Z1E",
236 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
237 DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1Z1E"),
241 .callback = init_nvs_nosave,
242 .ident = "Sony Vaio VGN-NW130D",
244 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
245 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-NW130D"),
249 .callback = init_nvs_nosave,
250 .ident = "Sony Vaio VPCCW29FX",
252 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
253 DMI_MATCH(DMI_PRODUCT_NAME, "VPCCW29FX"),
257 .callback = init_nvs_nosave,
258 .ident = "Averatec AV1020-ED2",
260 DMI_MATCH(DMI_SYS_VENDOR, "AVERATEC"),
261 DMI_MATCH(DMI_PRODUCT_NAME, "1000 Series"),
265 .callback = init_old_suspend_ordering,
266 .ident = "Asus A8N-SLI DELUXE",
268 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
269 DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI DELUXE"),
273 .callback = init_old_suspend_ordering,
274 .ident = "Asus A8N-SLI Premium",
276 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
277 DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI Premium"),
281 .callback = init_nvs_nosave,
282 .ident = "Sony Vaio VGN-SR26GN_P",
284 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
285 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR26GN_P"),
289 .callback = init_nvs_nosave,
290 .ident = "Sony Vaio VPCEB1S1E",
292 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
293 DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1S1E"),
297 .callback = init_nvs_nosave,
298 .ident = "Sony Vaio VGN-FW520F",
300 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
301 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW520F"),
305 .callback = init_nvs_nosave,
306 .ident = "Asus K54C",
308 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
309 DMI_MATCH(DMI_PRODUCT_NAME, "K54C"),
313 .callback = init_nvs_nosave,
314 .ident = "Asus K54HR",
316 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
317 DMI_MATCH(DMI_PRODUCT_NAME, "K54HR"),
323 static void acpi_sleep_dmi_check(void)
327 if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2012)
328 acpi_nvs_nosave_s3();
330 dmi_check_system(acpisleep_dmi_table);
334 * acpi_pm_freeze - Disable the GPEs and suspend EC transactions.
336 static int acpi_pm_freeze(void)
338 acpi_disable_all_gpes();
339 acpi_os_wait_events_complete();
340 acpi_ec_block_transactions();
345 * acpi_pre_suspend - Enable wakeup devices, "freeze" EC and save NVS.
347 static int acpi_pm_pre_suspend(void)
350 return suspend_nvs_save();
354 * __acpi_pm_prepare - Prepare the platform to enter the target state.
356 * If necessary, set the firmware waking vector and do arch-specific
357 * nastiness to get the wakeup code to the waking vector.
359 static int __acpi_pm_prepare(void)
361 int error = acpi_sleep_prepare(acpi_target_sleep_state);
363 acpi_target_sleep_state = ACPI_STATE_S0;
369 * acpi_pm_prepare - Prepare the platform to enter the target sleep
370 * state and disable the GPEs.
372 static int acpi_pm_prepare(void)
374 int error = __acpi_pm_prepare();
376 error = acpi_pm_pre_suspend();
381 static int find_powerf_dev(struct device *dev, void *data)
383 struct acpi_device *device = to_acpi_device(dev);
384 const char *hid = acpi_device_hid(device);
386 return !strcmp(hid, ACPI_BUTTON_HID_POWERF);
390 * acpi_pm_finish - Instruct the platform to leave a sleep state.
392 * This is called after we wake back up (or if entering the sleep state
395 static void acpi_pm_finish(void)
397 struct device *pwr_btn_dev;
398 u32 acpi_state = acpi_target_sleep_state;
400 acpi_ec_unblock_transactions();
403 if (acpi_state == ACPI_STATE_S0)
406 printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
408 acpi_disable_wakeup_devices(acpi_state);
409 acpi_leave_sleep_state(acpi_state);
411 /* reset firmware waking vector */
412 acpi_set_firmware_waking_vector((acpi_physical_address) 0);
414 acpi_target_sleep_state = ACPI_STATE_S0;
416 acpi_resume_power_resources();
418 /* If we were woken with the fixed power button, provide a small
419 * hint to userspace in the form of a wakeup event on the fixed power
420 * button device (if it can be found).
422 * We delay the event generation til now, as the PM layer requires
423 * timekeeping to be running before we generate events. */
424 if (!pwr_btn_event_pending)
427 pwr_btn_event_pending = false;
428 pwr_btn_dev = bus_find_device(&acpi_bus_type, NULL, NULL,
431 pm_wakeup_event(pwr_btn_dev, 0);
432 put_device(pwr_btn_dev);
437 * acpi_pm_start - Start system PM transition.
439 static void acpi_pm_start(u32 acpi_state)
441 acpi_target_sleep_state = acpi_state;
442 acpi_sleep_tts_switch(acpi_target_sleep_state);
443 acpi_scan_lock_acquire();
447 * acpi_pm_end - Finish up system PM transition.
449 static void acpi_pm_end(void)
451 acpi_scan_lock_release();
453 * This is necessary in case acpi_pm_finish() is not called during a
454 * failing transition to a sleep state.
456 acpi_target_sleep_state = ACPI_STATE_S0;
457 acpi_sleep_tts_switch(acpi_target_sleep_state);
459 #else /* !CONFIG_ACPI_SLEEP */
460 #define acpi_target_sleep_state ACPI_STATE_S0
461 static inline void acpi_sleep_dmi_check(void) {}
462 #endif /* CONFIG_ACPI_SLEEP */
464 #ifdef CONFIG_SUSPEND
465 static u32 acpi_suspend_states[] = {
466 [PM_SUSPEND_ON] = ACPI_STATE_S0,
467 [PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
468 [PM_SUSPEND_MEM] = ACPI_STATE_S3,
469 [PM_SUSPEND_MAX] = ACPI_STATE_S5
473 * acpi_suspend_begin - Set the target system sleep state to the state
474 * associated with given @pm_state, if supported.
476 static int acpi_suspend_begin(suspend_state_t pm_state)
478 u32 acpi_state = acpi_suspend_states[pm_state];
481 error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();
485 if (!sleep_states[acpi_state]) {
486 pr_err("ACPI does not support sleep state S%u\n", acpi_state);
490 acpi_pm_start(acpi_state);
495 * acpi_suspend_enter - Actually enter a sleep state.
498 * Flush caches and go to sleep. For STR we have to call arch-specific
499 * assembly, which in turn call acpi_enter_sleep_state().
500 * It's unfortunate, but it works. Please fix if you're feeling frisky.
502 static int acpi_suspend_enter(suspend_state_t pm_state)
504 acpi_status status = AE_OK;
505 u32 acpi_state = acpi_target_sleep_state;
508 ACPI_FLUSH_CPU_CACHE();
510 trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true);
511 switch (acpi_state) {
514 status = acpi_enter_sleep_state(acpi_state);
518 if (!acpi_suspend_lowlevel)
520 error = acpi_suspend_lowlevel();
523 pr_info(PREFIX "Low-level resume complete\n");
526 trace_suspend_resume(TPS("acpi_suspend"), acpi_state, false);
528 /* This violates the spec but is required for bug compatibility. */
529 acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
531 /* Reprogram control registers */
532 acpi_leave_sleep_state_prep(acpi_state);
534 /* ACPI 3.0 specs (P62) says that it's the responsibility
535 * of the OSPM to clear the status bit [ implying that the
536 * POWER_BUTTON event should not reach userspace ]
538 * However, we do generate a small hint for userspace in the form of
539 * a wakeup event. We flag this condition for now and generate the
540 * event later, as we're currently too early in resume to be able to
541 * generate wakeup events.
543 if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
544 acpi_event_status pwr_btn_status = ACPI_EVENT_FLAG_DISABLED;
546 acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);
548 if (pwr_btn_status & ACPI_EVENT_FLAG_SET) {
549 acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
551 pwr_btn_event_pending = true;
556 * Disable and clear GPE status before interrupt is enabled. Some GPEs
557 * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
558 * acpi_leave_sleep_state will reenable specific GPEs later
560 acpi_disable_all_gpes();
561 /* Allow EC transactions to happen. */
562 acpi_ec_unblock_transactions_early();
564 suspend_nvs_restore();
566 return ACPI_SUCCESS(status) ? 0 : -EFAULT;
569 static int acpi_suspend_state_valid(suspend_state_t pm_state)
575 case PM_SUSPEND_STANDBY:
577 acpi_state = acpi_suspend_states[pm_state];
579 return sleep_states[acpi_state];
585 static const struct platform_suspend_ops acpi_suspend_ops = {
586 .valid = acpi_suspend_state_valid,
587 .begin = acpi_suspend_begin,
588 .prepare_late = acpi_pm_prepare,
589 .enter = acpi_suspend_enter,
590 .wake = acpi_pm_finish,
595 * acpi_suspend_begin_old - Set the target system sleep state to the
596 * state associated with given @pm_state, if supported, and
597 * execute the _PTS control method. This function is used if the
598 * pre-ACPI 2.0 suspend ordering has been requested.
600 static int acpi_suspend_begin_old(suspend_state_t pm_state)
602 int error = acpi_suspend_begin(pm_state);
604 error = __acpi_pm_prepare();
610 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
613 static const struct platform_suspend_ops acpi_suspend_ops_old = {
614 .valid = acpi_suspend_state_valid,
615 .begin = acpi_suspend_begin_old,
616 .prepare_late = acpi_pm_pre_suspend,
617 .enter = acpi_suspend_enter,
618 .wake = acpi_pm_finish,
620 .recover = acpi_pm_finish,
623 static int acpi_freeze_begin(void)
625 acpi_scan_lock_acquire();
629 static void acpi_freeze_end(void)
631 acpi_scan_lock_release();
634 static const struct platform_freeze_ops acpi_freeze_ops = {
635 .begin = acpi_freeze_begin,
636 .end = acpi_freeze_end,
639 static void acpi_sleep_suspend_setup(void)
643 for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++)
644 if (acpi_sleep_state_supported(i))
647 suspend_set_ops(old_suspend_ordering ?
648 &acpi_suspend_ops_old : &acpi_suspend_ops);
649 freeze_set_ops(&acpi_freeze_ops);
652 #else /* !CONFIG_SUSPEND */
653 static inline void acpi_sleep_suspend_setup(void) {}
654 #endif /* !CONFIG_SUSPEND */
656 #ifdef CONFIG_HIBERNATION
657 static unsigned long s4_hardware_signature;
658 static struct acpi_table_facs *facs;
659 static bool nosigcheck;
661 void __init acpi_no_s4_hw_signature(void)
666 static int acpi_hibernation_begin(void)
670 error = nvs_nosave ? 0 : suspend_nvs_alloc();
672 acpi_pm_start(ACPI_STATE_S4);
677 static int acpi_hibernation_enter(void)
679 acpi_status status = AE_OK;
681 ACPI_FLUSH_CPU_CACHE();
683 /* This shouldn't return. If it returns, we have a problem */
684 status = acpi_enter_sleep_state(ACPI_STATE_S4);
685 /* Reprogram control registers */
686 acpi_leave_sleep_state_prep(ACPI_STATE_S4);
688 return ACPI_SUCCESS(status) ? 0 : -EFAULT;
691 static void acpi_hibernation_leave(void)
694 * If ACPI is not enabled by the BIOS and the boot kernel, we need to
698 /* Reprogram control registers */
699 acpi_leave_sleep_state_prep(ACPI_STATE_S4);
700 /* Check the hardware signature */
701 if (facs && s4_hardware_signature != facs->hardware_signature)
702 pr_crit("ACPI: Hardware changed while hibernated, success doubtful!\n");
703 /* Restore the NVS memory area */
704 suspend_nvs_restore();
705 /* Allow EC transactions to happen. */
706 acpi_ec_unblock_transactions_early();
709 static void acpi_pm_thaw(void)
711 acpi_ec_unblock_transactions();
712 acpi_enable_all_runtime_gpes();
715 static const struct platform_hibernation_ops acpi_hibernation_ops = {
716 .begin = acpi_hibernation_begin,
718 .pre_snapshot = acpi_pm_prepare,
719 .finish = acpi_pm_finish,
720 .prepare = acpi_pm_prepare,
721 .enter = acpi_hibernation_enter,
722 .leave = acpi_hibernation_leave,
723 .pre_restore = acpi_pm_freeze,
724 .restore_cleanup = acpi_pm_thaw,
728 * acpi_hibernation_begin_old - Set the target system sleep state to
729 * ACPI_STATE_S4 and execute the _PTS control method. This
730 * function is used if the pre-ACPI 2.0 suspend ordering has been
733 static int acpi_hibernation_begin_old(void)
737 * The _TTS object should always be evaluated before the _PTS object.
738 * When the old_suspended_ordering is true, the _PTS object is
739 * evaluated in the acpi_sleep_prepare.
741 acpi_sleep_tts_switch(ACPI_STATE_S4);
743 error = acpi_sleep_prepare(ACPI_STATE_S4);
747 error = suspend_nvs_alloc();
749 acpi_target_sleep_state = ACPI_STATE_S4;
750 acpi_scan_lock_acquire();
757 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
760 static const struct platform_hibernation_ops acpi_hibernation_ops_old = {
761 .begin = acpi_hibernation_begin_old,
763 .pre_snapshot = acpi_pm_pre_suspend,
764 .prepare = acpi_pm_freeze,
765 .finish = acpi_pm_finish,
766 .enter = acpi_hibernation_enter,
767 .leave = acpi_hibernation_leave,
768 .pre_restore = acpi_pm_freeze,
769 .restore_cleanup = acpi_pm_thaw,
770 .recover = acpi_pm_finish,
773 static void acpi_sleep_hibernate_setup(void)
775 if (!acpi_sleep_state_supported(ACPI_STATE_S4))
778 hibernation_set_ops(old_suspend_ordering ?
779 &acpi_hibernation_ops_old : &acpi_hibernation_ops);
780 sleep_states[ACPI_STATE_S4] = 1;
784 acpi_get_table(ACPI_SIG_FACS, 1, (struct acpi_table_header **)&facs);
786 s4_hardware_signature = facs->hardware_signature;
788 #else /* !CONFIG_HIBERNATION */
789 static inline void acpi_sleep_hibernate_setup(void) {}
790 #endif /* !CONFIG_HIBERNATION */
792 int acpi_suspend(u32 acpi_state)
794 suspend_state_t states[] = {
795 [1] = PM_SUSPEND_STANDBY,
796 [3] = PM_SUSPEND_MEM,
800 if (acpi_state < 6 && states[acpi_state])
801 return pm_suspend(states[acpi_state]);
807 static void acpi_power_off_prepare(void)
809 /* Prepare to power off the system */
810 acpi_sleep_prepare(ACPI_STATE_S5);
811 acpi_disable_all_gpes();
814 static void acpi_power_off(void)
816 /* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
817 printk(KERN_DEBUG "%s called\n", __func__);
819 acpi_enter_sleep_state(ACPI_STATE_S5);
822 int __init acpi_sleep_init(void)
824 char supported[ACPI_S_STATE_COUNT * 3 + 1];
825 char *pos = supported;
828 acpi_sleep_dmi_check();
830 sleep_states[ACPI_STATE_S0] = 1;
832 acpi_sleep_suspend_setup();
833 acpi_sleep_hibernate_setup();
835 if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
836 sleep_states[ACPI_STATE_S5] = 1;
837 pm_power_off_prepare = acpi_power_off_prepare;
838 pm_power_off = acpi_power_off;
842 for (i = 0; i < ACPI_S_STATE_COUNT; i++) {
844 pos += sprintf(pos, " S%d", i);
846 pr_info(PREFIX "(supports%s)\n", supported);
849 * Register the tts_notifier to reboot notifier list so that the _TTS
850 * object can also be evaluated when the system enters S5.
852 register_reboot_notifier(&tts_notifier);