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

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Date:   Thu, 5 Jul 2018 17:10:20 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     Thomas H4nig <haenig@...ifan.de>,
        Erik Schmauss <erik.schmauss@...el.com>,
        Lv Zheng <lv.zheng@...el.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        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 Thu, Jul 5, 2018 at 5:09 PM, Takashi Iwai <tiwai@...e.de> wrote:
> On Thu, 05 Jul 2018 16:00:14 +0200,
> Thomas H4nig wrote:
>>
>> Am 05.07.2018 um 14:12 schrieb Takashi Iwai:
>> > On Thu, 05 Jul 2018 12:41:03 +0200,
>> > Rafael J. Wysocki wrote:
>> >>
>> >> 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.
>> >
>> > OK, I'm building a 4.17.x test kernel with that revert, in OBS
>> > home:tiwai:bsc1099930 repo.
>> >
>> > Thomas, could you try later the kernel in
>> >   http://download.opensuse.org/repositories/home:/tiwai:/bsc1099930/standard/
>> > ?  It'll take an hour or so until the build finishes.
>>
>> With your new built kernel
>> 4.17.4-1.g6f23755-default
>>
>> the power button works again, so the revert solved the problem
>
> Thanks, that clarifies the cause.
> Adding Erik and Lv to Cc.
>
> I guess it's the side-effect by removing
>         acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
> in acpi_hw_disable_all_gpes().
>
> This function is called from acpi_power_off_prepare(), and the machine
> goes to power off without clearing the GPEs, hence it's woken up later
> unexpectedly.

That's correct.

We need to fix up that commit.  I'll try to prepare something.