linux-kernel - Re: [PATCH] ACPICA: Clear status of all events when entering sleep states

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Date:   Tue, 14 Aug 2018 12:09:10 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     "Schmauss, Erik" <erik.schmauss@...el.com>
Cc:     Linux ACPI <linux-acpi@...r.kernel.org>,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPICA: Clear status of all events when entering sleep states

On Monday, August 13, 2018 7:15:19 PM CEST Schmauss, Erik wrote:
> 
> > -----Original Message-----
> > From: linux-acpi-owner@...r.kernel.org [mailto:linux-acpi-
> > owner@...r.kernel.org] On Behalf Of Rafael J. Wysocki
> > Sent: Sunday, August 12, 2018 3:50 AM
> > To: Linux ACPI <linux-acpi@...r.kernel.org>
> > Cc: Paul Menzel <pmenzel@...gen.mpg.de>; Linux PM <linux-
> > pm@...r.kernel.org>; LKML <linux-kernel@...r.kernel.org>; Schmauss, Erik
> > <erik.schmauss@...el.com>
> > Subject: [PATCH] ACPICA: Clear status of all events when entering sleep states
> > 
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > 
> > Commit fa85015c0d95 (ACPICA: Clear status of all events when entering
> > S5) made the sleep state entry code in ACPICA clear the status of all ACPI events
> > when entering S5 to fix a functional regression reported against commit
> > 18996f2db918 (ACPICA: Events: Stop unconditionally clearing ACPI IRQs during
> > suspend/resume).  However, it is reported now that the regression also affects
> > system states other than S5 on some systems and causes them to wake up from
> > sleep prematurely.
> > 
> > For this reason, make the code in question clear the status of all ACPI events
> > when entering all sleep states (in addition to S5) to avoid the premature
> > wakeups (this may cause some wakeup events to be missed in theory, but the
> > likelihood of that is small and the change here simply restores the previous
> > behavior of the code).
> > 
> > Fixes: 18996f2db918 (ACPICA: Events: Stop unconditionally clearing ACPI IRQs
> > during suspend/resume)
> > Reported-by: Paul Menzel <pmenzel@...gen.mpg.de>
> > Tested-by: Paul Menzel <pmenzel@...gen.mpg.de>
> > Cc: 4.17+ <stable@...r.kernel.org> # 4.17+: fa85015c0d95 ACPICA: Clear
> > status ...
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >  drivers/acpi/acpica/hwsleep.c |   11 +++--------
> >  1 file changed, 3 insertions(+), 8 deletions(-)
> > 
> > Index: linux-pm/drivers/acpi/acpica/hwsleep.c
> > =================================================================
> > ==
> > --- linux-pm.orig/drivers/acpi/acpica/hwsleep.c
> > +++ linux-pm/drivers/acpi/acpica/hwsleep.c
> > @@ -56,14 +56,9 @@ acpi_status acpi_hw_legacy_sleep(u8 slee
> >  	if (ACPI_FAILURE(status)) {
> >  		return_ACPI_STATUS(status);
> >  	}
> > -	/*
> > -	 * If the target sleep state is S5, clear all GPEs and fixed events too
> > -	 */
> > -	if (sleep_state == ACPI_STATE_S5) {
> > -		status = acpi_hw_clear_acpi_status();
> > -		if (ACPI_FAILURE(status)) {
> > -			return_ACPI_STATUS(status);
> > -		}
> > +	status = acpi_hw_clear_acpi_status();
> > +	if (ACPI_FAILURE(status)) {
> > +		return_ACPI_STATUS(status);
> >  	}
> >  	acpi_gbl_system_awake_and_running = FALSE;
> > 
> 
> I'll backport this for the next ACPICA release

Thanks!