On Friday, June 24, 2016 02:59:24 AM Ocean HY1 He wrote: > > 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: rjwysocki@xxxxxxxxx [mailto:rjwysocki@xxxxxxxxx] On Behalf Of > > Rafael J. Wysocki > > Sent: Thursday, June 23, 2016 9:13 PM > > To: Ocean HY1 He > > Cc: Rafael J. Wysocki; lenb@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; David Tanaka; Nagananda Chumbalkar > > Subject: Re: [PATCH] ACPI: Execute the _PTS method when system reboot > > > > On Thu, Jun 23, 2016 at 2:55 PM, Ocean HY1 He <hehy1@xxxxxxxxxx> > > wrote: > > > 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. > > > > Not in general. > > > > In particular, wakeup devices that would be set up for S5 need not be > > set up for that. Also the mechanism by which transitions to S5 are > > entered is different from the reboot one, at least from the OS > > perspective. > > > > > Thus _PTS should be executed when reboot. > > > > No, it doesn't follow. > > > > > 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. > > > > Yes, it does. Maybe it shouldn't? > > > > It may not hurt to call _PTS before reboot too, but is it guaranteed > > to work across the board on all systems everywhere? > > > I try to clarify the key point of this case: does devices should go to S5(shutdown) when reboot? > > I think the answer is yes. > And It has no hurt to let devices go to S5 before reboot is invoked, here is the reasons: S5 is a platform (system) state, not a device state. You seem to be confusing platforms with devices. > #1 The new _PTS codes block nothing thus reboot can be guaranteed to be invoked eventually. > #2. Devices are mandatory to support S5 state, this means go to S5 could be a safe trip. > #3 Reboot would cause devices re-initialization from the scratch. > > What's your decision then? ;-) I guess you can argue that since _TTS is already executed in the reboot path, it might be good to execute _PTS in that path too and that might help to avoid issues in some cases. That is a reasonable argument, but then there still is the question if that is not going to break anything. I guess that cannot be answered without trying, so the simplest patch would be to add a _PTS evaulation to the existing notifier (and maybe change the notifiers name to reflect the fact that it's not for _TTS ony any more). Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
