linux-kernel - Re: [PATCH] ACPI: do not fail suspend if unable to configure wakeup

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Date:	Tue, 18 Nov 2014 16:48:42 -0800
From:	Dmitry Torokhov <dtor@...omium.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Dmitry Torokhov <dtor@...omium.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Benson Leung <bleung@...omium.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI: do not fail suspend if unable to configure wakeup

On Tue, Nov 18, 2014 at 5:01 PM, Rafael J. Wysocki <rjw@...ysocki.net> wrote:
> On Tuesday, November 18, 2014 04:14:49 PM Dmitry Torokhov wrote:
>> On Tue, Nov 18, 2014 at 4:20 PM, Rafael J. Wysocki <rjw@...ysocki.net> wrote:
>> > It goes again below with a changelog, but since technically it is a regression
>> > fix, I'd like to push it for "stable" too.  I suppose that the commit that
>> > things stopped working after is a76e9bd89ae7 (i2c: attach/detach I2C client
>> > device to the ACPI power domain).  Is that correct?
>>
>> Yes.
>
> OK
>
>> > --
>> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> > Subject: ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up
>> >
>> > As reported by Dmitry, on some Chromebooks there are devices with
>> > corresponding ACPI objects and with unusual system wakeup
>> > configuration.  Namely, they technically are wakeup-capable, but the
>> > wakeup is handled via a platform-specific out-of-band mechanism
>> > rather than by standard ACPI means.
>>
>> I think they are using standard ACPI wakeup methods, but in a very perverted
>> way: there is "shadow" ACPI sleep button corresponding to the GPIO assigned
>> to the trackpad or touchscreen; it is just not tied to touchpad/touchscreen
>> device in DSDT.
>
> OK
>
> This:
>
> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Subject: ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up
>
> As reported by Dmitry, on some Chromebooks there are devices with
> corresponding ACPI objects and with unusual system wakeup
> configuration.  Namely, they technically are wakeup-capable, but the
> wakeup is handled via a platform-specific out-of-band mechanism and
> the ACPI PM layer has no information on the wakeup capability.  As
> a result, device_may_wakeup(dev) called from acpi_dev_suspend_late()
> returns 'true' for those devices, but the wakeup.flags.valid flag is
> unset for the corresponding ACPI device objects, so acpi_device_wakeup()
> reproducibly fails for them causing acpi_dev_suspend_late() to return
> an error code.  The entire system suspend is then aborted and the
> machines in question cannot suspend at all.
>
> Address the problem by ignoring the device_may_wakeup(dev) return
> value in acpi_dev_suspend_late() if the ACPI companion of the device
> being handled has wakeup.flags.valid unset (in which case it is clear
> that the wakeup is supposed to be handled by other means).
>
> This fixes a regression introduced by commit a76e9bd89ae7 (i2c:
> attach/detach I2C client device to the ACPI power domain) as the
> affected systems could suspend and resume successfully before that
> commit.
>
> Fixes: a76e9bd89ae7 (i2c: attach/detach I2C client device to the ACPI power domain)
> Reported-by: Dmitry Torokhov <dtor@...omium.org>

Excellent, thank you Rafael.

Reviewed-by: Dmitry Torokhov <dtor@...omium.org>

> Cc: 3.13+ <stable@...r.kernel.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/acpi/device_pm.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-pm/drivers/acpi/device_pm.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/device_pm.c
> +++ linux-pm/drivers/acpi/device_pm.c
> @@ -878,7 +878,7 @@ int acpi_dev_suspend_late(struct device
>                 return 0;
>
>         target_state = acpi_target_system_state();
> -       wakeup = device_may_wakeup(dev);
> +       wakeup = device_may_wakeup(dev) && acpi_device_can_wakeup(adev);
>         error = acpi_device_wakeup(adev, target_state, wakeup);
>         if (wakeup && error)
>                 return error;
>
--
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