Re: [PATCH v2] pinctrl: amd: Clear S4 wake bits when firmware has _AEI

[Mario Limonciello <mario.limonciello@amd.com>]

On 10/7/26 06:27, Linus Walleij wrote:
> On Mon, Oct 5, 2026 at 8:02 PM Mario Limonciello
> <mario.limonciello@amd.com> wrote:
> 
>> Commit ffe8a0c6b552 ("pinctrl-amd: Don't clear S4 wake bits at probe")
>> preserves firmware-programmed S4 wake sources because some PCIe devices
>> rely on them for Wake-on-LAN. The system that motivated that change does
>> not expose ACPI GPIO events through _AEI.
>>
>> On a Chuwi CoreBook Plus, firmware exposes _AEI but also leaves the S4/S5
>> wake bit set for GPIO 24. This causes the machine to power back on
>> immediately after shutdown even though Wake-on-LAN is not enabled.
>>
>> GPIO register dumps show that the only relevant difference is bit 15 on
>> GPIO 24. Clearing that bit makes the machine remain off. GPIO 24 is not
>> itself listed in _AEI, so _AEI is not a per-pin indication of which pins
>> the OS manages; it is a platform level signal of which wake model the
>> firmware follows.
>>
>> Use that signal to decide what to clear. Continue clearing S0i3/S3 bits on
>> every system. Clear S4 bits when firmware exposes _AEI, indicating that the
>> platform hands GPIO events to the OS, but preserve S4 bits when _AEI is
>> absent so that firmware-programmed sources such as PCIe PME that bypass the
>> GPIO IRQ wake API keep working.
>>
>> A platform that exposes _AEI for some pins while routing a wake capable
>> device through a raw GPIO not listed in _AEI would lose that wake source
>> unless firmware re-arms it during the sleep transition. No such system has
>> been reported.
>>
>> Fixes: ffe8a0c6b552 ("pinctrl-amd: Don't clear S4 wake bits at probe")
>> Reported-by: Olzhas Marat <marat.olzhas@gmail.com>
>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=222041
>> Cc: stable@vger.kernel.org
>> Tested-by: Olzhas Marat <marat.olzhas@gmail.com>
>> Reviewed-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> 
> Patch applied for fixes.
> 
> Yours,
> Linus Walleij

Thanks!

Next cycle I'll send out a change to drop the #ifdef CONFIG_ACPI (there 
is a change in linux-next that adds a stub).