Hi Rafael, Please see my reply in below. Regards, Ocean He SW Development Dept. Beijing Design Center Enterprise Product Group Mobile: 18911778926 E-mail: hehy1@xxxxxxxxxx No.6 Chuang Ye Road, Haidian District, Beijing, China 100085 > -----Original Message----- > From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx] > Sent: Wednesday, June 22, 2016 7:56 AM > To: Ocean HY1 He > Cc: lenb@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; David Tanaka; Nagananda Chumbalkar > Subject: Re: [PATCH] ACPI: Execute the _PTS method when system reboot > > 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? > In ACPI spec, there is no explicit words saying _PTS should be executed when reboot. But reboot could be equal to the process S0->S5->S0. Thus _PTS should be executed when reboot. I am thinking this is the same as _TTS. In ACPI spec, there is also no explicit words saying _TTS should be executed when reboot. But kernel executes _TTS when reboot indeed. > > Signed-off-by: Ocean He <hehy1@xxxxxxxxxx> > > Signed-off-by: Nagananda Chumbalkar <nchumbalkar@xxxxxxxxxx> > > --- > > 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? > If execute _PTS method in tts_notify_reboot(), then it would break definition of tts_notify_reboot(). My intention is to keep new codes has limited impact on existed codes. Of course, it's possible to merge _TTS and _PTS into one unified notifier. The advantage is more actions could be added into the unified notifier in future. Which way you prefer? > > + > > return 0; > > } > > > > Thanks, > Rafael ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
