linux-kernel - Re: [PATCH 2/2] gpiolib-acpi: Don't set GPIOs for wakeup in S3 mode

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Date:   Mon, 23 Jan 2023 19:33:27 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     "Limonciello, Mario" <Mario.Limonciello@....com>
Cc:     Raul Rangel <rrangel@...omium.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Wolfram Sang <wsa@...nel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Nathan Smythe <ncsmythe@...uboak.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Mark Hasemeyer <markhas@...omium.org>
Subject: Re: [PATCH 2/2] gpiolib-acpi: Don't set GPIOs for wakeup in S3 mode

On Mon, Jan 23, 2023 at 04:06:59PM +0000, Limonciello, Mario wrote:
> > From: Raul Rangel <rrangel@...omium.org>
> > Sent: Monday, January 23, 2023 09:55
> > On Mon, Jan 23, 2023 at 8:03 AM Bartosz Golaszewski <brgl@...ev.pl>
> > wrote:
> > > On Sat, Jan 21, 2023 at 2:48 PM Mario Limonciello
> > > <mario.limonciello@....com> wrote:

...

> > > > +                       /* avoid suspend issues with GPIOs when systems are using
> > S3 */
> > > > +                       if (wake_capable && acpi_gbl_FADT.flags &
> > ACPI_FADT_LOW_POWER_S0)
> > > >                                 *wake_capable = info.wake_capable;
> > > >
> > > >                         return irq;

...

> > We still need to figure out a proper fix for this. If you read my post
> > here: https://gitlab.freedesktop.org/drm/amd/-/issues/2357#note_1732372
> > I think we misinterpreted what the SharedAndWake bit is used for. To
> > me it sounds like it's only valid for HW Reduced ACPI platforms, and
> > S0ix. My changes made it so we call `dev_pm_set_wake_irq` when the
> > Wake bit is set. Does anyone have any additional context on the Wake
> > bit? I think we either need to make `dev_pm_set_wake_irq` (or a
> > variant) only enable the wake on S0i3, or we can teach the ACPI
> > subsystem to manage arming the IRQ's wake bit. Kind of like we already
> > manage the GPE events for the device.
> 
> There is an FADT flag for HW reduced (ACPI_FADT_HW_REDUCED).  So
> maybe something on top of my change to look at that too?
> 
> IE:
> if (wake_capable && (acpi_gbl_FADT.flags & (ACPI_FADT_LOW_POWER_S0 | ACPI_FADT_HW_REDUCED)

I'm not sure why we are talking about HW reduced case?
In HP reduced case IIRC the GPE are absent as a class.

-- 
With Best Regards,
Andy Shevchenko