On Monday, May 09, 2016 05:50:11 AM Ocean HY1 He wrote: > The _PTS control method is defined in the section 7.4.1 of acpi 6.0 > spec. The _PTS control method is executed by the OS during the sleep > transition process for S1, S2, S3, S4, and for orderly S5 shutdown. > The sleeping state value (For example, 1, 2, 3, 4 or 5 for the S5 > soft-off state) is passed to the _PTS control method. This method > is called after OSPM has notified native device drivers of the sleep > state transition and before the OSPM has had a chance to fully > prepare the system for a sleep state transition. > > The _PTS control method provides the BIOS a mechanism for performing > some housekeeping, such as writing the sleep type value to the embedded > controller, before entering the system sleeping state. > > According to section 7.5 of acpi 6.0 spec, _PTS should run after _TTS. > > Thus, a _PTS block notifier is added to the reboot notifier list so that > the _PTS object will also be evaluated when the system reboot.
So I understand why it may be necessary to evaluate _PTS before entering S5, but I'm totally unsure about reboot. What does reboot have to do with S5? > Signed-off-by: Ocean He <[email protected]> > Signed-off-by: Nagananda Chumbalkar <[email protected]> > --- > drivers/acpi/sleep.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c > index 2a8b596..8b290fb 100644 > --- a/drivers/acpi/sleep.c > +++ b/drivers/acpi/sleep.c > @@ -55,6 +55,26 @@ static struct notifier_block tts_notifier = { > .priority = 0, > }; > > +static int pts_notify_reboot(struct notifier_block *this, > + unsigned long code, void *x) > +{ > + acpi_status status; > + > + status = acpi_execute_simple_method(NULL, "\\_PTS", ACPI_STATE_S5); > + if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { > + /* It won't break anything. */ > + printk(KERN_NOTICE "Failure in evaluating _PTS object\n"); > + } > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block pts_notifier = { > + .notifier_call = pts_notify_reboot, > + .next = NULL, > + .priority = 0, > +}; > + > static int acpi_sleep_prepare(u32 acpi_state) > { > #ifdef CONFIG_ACPI_SLEEP > @@ -896,5 +916,12 @@ int __init acpi_sleep_init(void) > * object can also be evaluated when the system enters S5. > */ > register_reboot_notifier(&tts_notifier); > + > + /* > + * According to section 7.5 of acpi 6.0 spec, _PTS should run after > + * _TTS when the system enters S5. > + */ > + register_reboot_notifier(&pts_notifier); Why do you have to add a second notifier? Why can't _TTS and _PTS be evaluated from one notifier? > + > return 0; > } > Thanks, Rafael
