linux-kernel - Re: [REGRESSION 4.17] Spurious wakeup / reboot with power button

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Date:   Thu, 05 Jul 2018 12:41:03 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Thomas Hänig <haenig@...ifan.de>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [REGRESSION 4.17] Spurious wakeup / reboot with power button

On Thursday, July 5, 2018 11:50:11 AM CEST Takashi Iwai wrote:
> On Thu, 05 Jul 2018 11:34:59 +0200,
> Rafael J. Wysocki wrote:
> > 
> > Hi,
> > 
> > On Thu, Jul 5, 2018 at 9:05 AM, Takashi Iwai <tiwai@...e.de> wrote:
> > > Hi,
> > >
> > > we've got a regression report since 4.17 about the behavior of
> > > power-off with the power button.  When a machine is powered off with
> > > the power button on desktop, it reboots after a few seconds instead of
> > > power down.
> > >
> > > The manual power down via "systemctl poweroff" works fine, so it's
> > > possibly some spurious wakeup by the power button action, and some
> > > ACPI-related change is suspected.
> > > The regression still remains in 4.18-rc3.
> > 
> > There are only a few ACPI commits directly related to power management
> > between 4.16 and 4.17 and none of them looks particularly suspicious.
> 
> OK, interesting.
> 
> > It looks like the power button state may not be cleared sufficiently
> > after it's been pressed which is now visible for some reason.
> 
> Hmm, where can such a state remain?  Since it happens after the
> machine turned off, some (ACPI) wakeup bits?

Basically, yes.

It looks like a GPE may remain active which then triggers wakeup after
shutdown.

On a hunch, I'm wondering if reverting commit

18996f2db918 ACPICA: Events: Stop unconditionally clearing ACPI IRQs during suspend/resume

(may not revert clearly, though) makes any difference.

Thanks,
Rafael