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)
325 dmi_check_system(acpisleep_dmi_table);
329 * acpi_pm_freeze - Disable the GPEs and suspend EC transactions.
331 static int acpi_pm_freeze(void)
333 acpi_disable_all_gpes();
334 acpi_os_wait_events_complete();
335 acpi_ec_block_transactions();
340 * acpi_pre_suspend - Enable wakeup devices, "freeze" EC and save NVS.
342 static int acpi_pm_pre_suspend(void)
345 return suspend_nvs_save();
349 * __acpi_pm_prepare - Prepare the platform to enter the target state.
351 * If necessary, set the firmware waking vector and do arch-specific
352 * nastiness to get the wakeup code to the waking vector.
354 static int __acpi_pm_prepare(void)
356 int error = acpi_sleep_prepare(acpi_target_sleep_state);
358 acpi_target_sleep_state = ACPI_STATE_S0;
364 * acpi_pm_prepare - Prepare the platform to enter the target sleep
365 * state and disable the GPEs.
367 static int acpi_pm_prepare(void)
369 int error = __acpi_pm_prepare();
371 error = acpi_pm_pre_suspend();
376 static int find_powerf_dev(struct device *dev, void *data)
378 struct acpi_device *device = to_acpi_device(dev);
379 const char *hid = acpi_device_hid(device);
381 return !strcmp(hid, ACPI_BUTTON_HID_POWERF);
385 * acpi_pm_finish - Instruct the platform to leave a sleep state.
387 * This is called after we wake back up (or if entering the sleep state
390 static void acpi_pm_finish(void)
392 struct device *pwr_btn_dev;
393 u32 acpi_state = acpi_target_sleep_state;
395 acpi_ec_unblock_transactions();
398 if (acpi_state == ACPI_STATE_S0)
401 printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
403 acpi_disable_wakeup_devices(acpi_state);
404 acpi_leave_sleep_state(acpi_state);
406 /* reset firmware waking vector */
407 acpi_set_firmware_waking_vector((acpi_physical_address) 0);
409 acpi_target_sleep_state = ACPI_STATE_S0;
411 acpi_resume_power_resources();
413 /* If we were woken with the fixed power button, provide a small
414 * hint to userspace in the form of a wakeup event on the fixed power
415 * button device (if it can be found).
417 * We delay the event generation til now, as the PM layer requires
418 * timekeeping to be running before we generate events. */
419 if (!pwr_btn_event_pending)
422 pwr_btn_event_pending = false;
423 pwr_btn_dev = bus_find_device(&acpi_bus_type, NULL, NULL,
426 pm_wakeup_event(pwr_btn_dev, 0);
427 put_device(pwr_btn_dev);
432 * acpi_pm_start - Start system PM transition.
434 static void acpi_pm_start(u32 acpi_state)
436 acpi_target_sleep_state = acpi_state;
437 acpi_sleep_tts_switch(acpi_target_sleep_state);
438 acpi_scan_lock_acquire();
442 * acpi_pm_end - Finish up system PM transition.
444 static void acpi_pm_end(void)
446 acpi_scan_lock_release();
448 * This is necessary in case acpi_pm_finish() is not called during a
449 * failing transition to a sleep state.
451 acpi_target_sleep_state = ACPI_STATE_S0;
452 acpi_sleep_tts_switch(acpi_target_sleep_state);
454 #else /* !CONFIG_ACPI_SLEEP */
455 #define acpi_target_sleep_state ACPI_STATE_S0
456 static inline void acpi_sleep_dmi_check(void) {}
457 #endif /* CONFIG_ACPI_SLEEP */
459 #ifdef CONFIG_SUSPEND
460 static u32 acpi_suspend_states[] = {
461 [PM_SUSPEND_ON] = ACPI_STATE_S0,
462 [PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
463 [PM_SUSPEND_MEM] = ACPI_STATE_S3,
464 [PM_SUSPEND_MAX] = ACPI_STATE_S5
468 * acpi_suspend_begin - Set the target system sleep state to the state
469 * associated with given @pm_state, if supported.
471 static int acpi_suspend_begin(suspend_state_t pm_state)
473 u32 acpi_state = acpi_suspend_states[pm_state];
476 error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();
480 if (!sleep_states[acpi_state]) {
481 pr_err("ACPI does not support sleep state S%u\n", acpi_state);
485 acpi_pm_start(acpi_state);
490 * acpi_suspend_enter - Actually enter a sleep state.
493 * Flush caches and go to sleep. For STR we have to call arch-specific
494 * assembly, which in turn call acpi_enter_sleep_state().
495 * It's unfortunate, but it works. Please fix if you're feeling frisky.
497 static int acpi_suspend_enter(suspend_state_t pm_state)
499 acpi_status status = AE_OK;
500 u32 acpi_state = acpi_target_sleep_state;
503 ACPI_FLUSH_CPU_CACHE();
505 trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true);
506 switch (acpi_state) {
509 status = acpi_enter_sleep_state(acpi_state);
513 if (!acpi_suspend_lowlevel)
515 error = acpi_suspend_lowlevel();
518 pr_info(PREFIX "Low-level resume complete\n");
521 trace_suspend_resume(TPS("acpi_suspend"), acpi_state, false);
523 /* This violates the spec but is required for bug compatibility. */
524 acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
526 /* Reprogram control registers */
527 acpi_leave_sleep_state_prep(acpi_state);
529 /* ACPI 3.0 specs (P62) says that it's the responsibility
530 * of the OSPM to clear the status bit [ implying that the
531 * POWER_BUTTON event should not reach userspace ]
533 * However, we do generate a small hint for userspace in the form of
534 * a wakeup event. We flag this condition for now and generate the
535 * event later, as we're currently too early in resume to be able to
536 * generate wakeup events.
538 if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
539 acpi_event_status pwr_btn_status = ACPI_EVENT_FLAG_DISABLED;
541 acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);
543 if (pwr_btn_status & ACPI_EVENT_FLAG_SET) {
544 acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
546 pwr_btn_event_pending = true;
551 * Disable and clear GPE status before interrupt is enabled. Some GPEs
552 * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
553 * acpi_leave_sleep_state will reenable specific GPEs later
555 acpi_disable_all_gpes();
556 /* Allow EC transactions to happen. */
557 acpi_ec_unblock_transactions_early();
559 suspend_nvs_restore();
561 return ACPI_SUCCESS(status) ? 0 : -EFAULT;
564 static int acpi_suspend_state_valid(suspend_state_t pm_state)
570 case PM_SUSPEND_STANDBY:
572 acpi_state = acpi_suspend_states[pm_state];
574 return sleep_states[acpi_state];
580 static const struct platform_suspend_ops acpi_suspend_ops = {
581 .valid = acpi_suspend_state_valid,
582 .begin = acpi_suspend_begin,
583 .prepare_late = acpi_pm_prepare,
584 .enter = acpi_suspend_enter,
585 .wake = acpi_pm_finish,
590 * acpi_suspend_begin_old - Set the target system sleep state to the
591 * state associated with given @pm_state, if supported, and
592 * execute the _PTS control method. This function is used if the
593 * pre-ACPI 2.0 suspend ordering has been requested.
595 static int acpi_suspend_begin_old(suspend_state_t pm_state)
597 int error = acpi_suspend_begin(pm_state);
599 error = __acpi_pm_prepare();
605 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
608 static const struct platform_suspend_ops acpi_suspend_ops_old = {
609 .valid = acpi_suspend_state_valid,
610 .begin = acpi_suspend_begin_old,
611 .prepare_late = acpi_pm_pre_suspend,
612 .enter = acpi_suspend_enter,
613 .wake = acpi_pm_finish,
615 .recover = acpi_pm_finish,
618 static int acpi_freeze_begin(void)
620 acpi_scan_lock_acquire();
624 static void acpi_freeze_end(void)
626 acpi_scan_lock_release();
629 static const struct platform_freeze_ops acpi_freeze_ops = {
630 .begin = acpi_freeze_begin,
631 .end = acpi_freeze_end,
634 static void acpi_sleep_suspend_setup(void)
638 for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++)
639 if (acpi_sleep_state_supported(i))
642 suspend_set_ops(old_suspend_ordering ?
643 &acpi_suspend_ops_old : &acpi_suspend_ops);
644 freeze_set_ops(&acpi_freeze_ops);
647 #else /* !CONFIG_SUSPEND */
648 static inline void acpi_sleep_suspend_setup(void) {}
649 #endif /* !CONFIG_SUSPEND */
651 #ifdef CONFIG_HIBERNATION
652 static unsigned long s4_hardware_signature;
653 static struct acpi_table_facs *facs;
654 static bool nosigcheck;
656 void __init acpi_no_s4_hw_signature(void)
661 static int acpi_hibernation_begin(void)
665 error = nvs_nosave ? 0 : suspend_nvs_alloc();
667 acpi_pm_start(ACPI_STATE_S4);
672 static int acpi_hibernation_enter(void)
674 acpi_status status = AE_OK;
676 ACPI_FLUSH_CPU_CACHE();
678 /* This shouldn't return. If it returns, we have a problem */
679 status = acpi_enter_sleep_state(ACPI_STATE_S4);
680 /* Reprogram control registers */
681 acpi_leave_sleep_state_prep(ACPI_STATE_S4);
683 return ACPI_SUCCESS(status) ? 0 : -EFAULT;
686 static void acpi_hibernation_leave(void)
689 * If ACPI is not enabled by the BIOS and the boot kernel, we need to
693 /* Reprogram control registers */
694 acpi_leave_sleep_state_prep(ACPI_STATE_S4);
695 /* Check the hardware signature */
696 if (facs && s4_hardware_signature != facs->hardware_signature)
697 pr_crit("ACPI: Hardware changed while hibernated, success doubtful!\n");
698 /* Restore the NVS memory area */
699 suspend_nvs_restore();
700 /* Allow EC transactions to happen. */
701 acpi_ec_unblock_transactions_early();
704 static void acpi_pm_thaw(void)
706 acpi_ec_unblock_transactions();
707 acpi_enable_all_runtime_gpes();
710 static const struct platform_hibernation_ops acpi_hibernation_ops = {
711 .begin = acpi_hibernation_begin,
713 .pre_snapshot = acpi_pm_prepare,
714 .finish = acpi_pm_finish,
715 .prepare = acpi_pm_prepare,
716 .enter = acpi_hibernation_enter,
717 .leave = acpi_hibernation_leave,
718 .pre_restore = acpi_pm_freeze,
719 .restore_cleanup = acpi_pm_thaw,
723 * acpi_hibernation_begin_old - Set the target system sleep state to
724 * ACPI_STATE_S4 and execute the _PTS control method. This
725 * function is used if the pre-ACPI 2.0 suspend ordering has been
728 static int acpi_hibernation_begin_old(void)
732 * The _TTS object should always be evaluated before the _PTS object.
733 * When the old_suspended_ordering is true, the _PTS object is
734 * evaluated in the acpi_sleep_prepare.
736 acpi_sleep_tts_switch(ACPI_STATE_S4);
738 error = acpi_sleep_prepare(ACPI_STATE_S4);
742 error = suspend_nvs_alloc();
744 acpi_target_sleep_state = ACPI_STATE_S4;
745 acpi_scan_lock_acquire();
752 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
755 static const struct platform_hibernation_ops acpi_hibernation_ops_old = {
756 .begin = acpi_hibernation_begin_old,
758 .pre_snapshot = acpi_pm_pre_suspend,
759 .prepare = acpi_pm_freeze,
760 .finish = acpi_pm_finish,
761 .enter = acpi_hibernation_enter,
762 .leave = acpi_hibernation_leave,
763 .pre_restore = acpi_pm_freeze,
764 .restore_cleanup = acpi_pm_thaw,
765 .recover = acpi_pm_finish,
768 static void acpi_sleep_hibernate_setup(void)
770 if (!acpi_sleep_state_supported(ACPI_STATE_S4))
773 hibernation_set_ops(old_suspend_ordering ?
774 &acpi_hibernation_ops_old : &acpi_hibernation_ops);
775 sleep_states[ACPI_STATE_S4] = 1;
779 acpi_get_table(ACPI_SIG_FACS, 1, (struct acpi_table_header **)&facs);
781 s4_hardware_signature = facs->hardware_signature;
783 #else /* !CONFIG_HIBERNATION */
784 static inline void acpi_sleep_hibernate_setup(void) {}
785 #endif /* !CONFIG_HIBERNATION */
787 int acpi_suspend(u32 acpi_state)
789 suspend_state_t states[] = {
790 [1] = PM_SUSPEND_STANDBY,
791 [3] = PM_SUSPEND_MEM,
795 if (acpi_state < 6 && states[acpi_state])
796 return pm_suspend(states[acpi_state]);
802 static void acpi_power_off_prepare(void)
804 /* Prepare to power off the system */
805 acpi_sleep_prepare(ACPI_STATE_S5);
806 acpi_disable_all_gpes();
809 static void acpi_power_off(void)
811 /* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
812 printk(KERN_DEBUG "%s called\n", __func__);
814 acpi_enter_sleep_state(ACPI_STATE_S5);
817 int __init acpi_sleep_init(void)
819 char supported[ACPI_S_STATE_COUNT * 3 + 1];
820 char *pos = supported;
823 acpi_sleep_dmi_check();
825 sleep_states[ACPI_STATE_S0] = 1;
827 acpi_sleep_suspend_setup();
828 acpi_sleep_hibernate_setup();
830 if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
831 sleep_states[ACPI_STATE_S5] = 1;
832 pm_power_off_prepare = acpi_power_off_prepare;
833 pm_power_off = acpi_power_off;
837 for (i = 0; i < ACPI_S_STATE_COUNT; i++) {
839 pos += sprintf(pos, " S%d", i);
841 pr_info(PREFIX "(supports%s)\n", supported);
844 * Register the tts_notifier to reboot notifier list so that the _TTS
845 * object can also be evaluated when the system enters S5.
847 register_reboot_notifier(&tts_notifier);