RE: [PATCH] ACPICA: Clear status of all events when entering sleep states

["Schmauss, Erik" <erik.schmauss@intel.com>]

> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Rafael J. Wysocki
> Sent: Sunday, August 12, 2018 3:50 AM
> To: Linux ACPI <linux-acpi@vger.kernel.org>
> Cc: Paul Menzel <pmenzel@molgen.mpg.de>; Linux PM <linux-
> pm@vger.kernel.org>; LKML <linux-kernel@vger.kernel.org>; Schmauss, Erik
> <erik.schmauss@intel.com>
> Subject: [PATCH] ACPICA: Clear status of all events when entering sleep states
> 
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.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@molgen.mpg.de>
> Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
> Cc: 4.17+ <stable@vger.kernel.org> # 4.17+: fa85015c0d95 ACPICA: Clear
> status ...
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.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,
Erik