linux-kernel - Re: [PATCH] platform/x86: intel_int0002_vgpio: Only bind to the INT0002 dev when using s2idle

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Date:   Wed, 8 Apr 2020 15:11:51 +0300
From:   Maxim Mikityanskiy <maxtram95@...il.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "5 . 3+" <stable@...r.kernel.org>
Subject: Re: [PATCH] platform/x86: intel_int0002_vgpio: Only bind to the
 INT0002 dev when using s2idle

On Wed, Apr 8, 2020 at 12:31 AM Hans de Goede <hdegoede@...hat.com> wrote:
>
> Commit 871f1f2bcb01 ("platform/x86: intel_int0002_vgpio: Only implement
> irq_set_wake on Bay Trail") stopped passing irq_set_wake requests on to
> the parents IRQ because this was breaking suspend (causing immediate
> wakeups) on an Asus E202SA.
>
> This workaround for this issue is mostly fine, on most Cherry Trail
> devices where we need the INT0002 device for wakeups by e.g. USB kbds,
> the parent IRQ is shared with the ACPI SCI and that is marked as wakeup
> anyways.
>
> But not on all devices, specifically on a Medion Akoya E1239T there is
> no SCI at all, and because the irq_set_wake request is not passed on to
> the parent IRQ, wake up by the builtin USB kbd does not work here.
>
> So the workaround for the Asus E202SA immediate wake problem is causing
> problems elsewhere; and in hindsight it is not the correct fix,
> the Asus E202SA uses Airmont CPU cores, but this does not mean it is a
> Cherry Trail based device, Brasswell uses Airmont CPU cores too and this
> actually is a Braswell device.
>
> Most (all?) Braswell devices use classic S3 mode suspend rather then
> s2idle suspend and in this case directly dealing with PME events as
> the INT0002 driver does likely is not the best idea, so that this is
> causing issues is not surprising.
>
> Replace the workaround of not passing irq_set_wake requests on to the
> parents IRQ, by not binding to the INT0002 device when s2idle is not used.
> This fixes USB kbd wakeups not working on some Cherry Trail devices,
> while still avoiding mucking with the wakeup flags on the Asus E202SA
> (and other Brasswell devices).

I tested this patch over kernel 5.6.2 on Asus E202SA and didn't notice
any regressions. Wakeup by opening lid, by pressing a button on
keyboard, by USB keyboard — all seem to work fine. So, if appropriate:

Tested-by: Maxim Mikityanskiy <maxtram95@...il.com>

I have a question though. After your patch this driver will basically
be a no-op on my laptop. Does it mean I don't even need it in the
first place? What about the IRQ storm this driver is meant to deal
with — does it never happen on Braswell? What are the reproduction
steps to verify my hardware is not affected? I have that INT0002
device, so I'm worried it may cause issues if not bound to the driver.

> Cc: Maxim Mikityanskiy <maxtram95@...il.com>
> Cc: 5.3+ <stable@...r.kernel.org> # 5.3+
> Fixes: 871f1f2bcb01 ("platform/x86: intel_int0002_vgpio: Only implement irq_set_wake on Bay Trail")
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
>  drivers/platform/x86/intel_int0002_vgpio.c | 18 +++++-------------
>  1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/platform/x86/intel_int0002_vgpio.c b/drivers/platform/x86/intel_int0002_vgpio.c
> index 55f088f535e2..e8bec72d3823 100644
> --- a/drivers/platform/x86/intel_int0002_vgpio.c
> +++ b/drivers/platform/x86/intel_int0002_vgpio.c
> @@ -143,21 +143,9 @@ static struct irq_chip int0002_byt_irqchip = {
>         .irq_set_wake           = int0002_irq_set_wake,
>  };
>
> -static struct irq_chip int0002_cht_irqchip = {
> -       .name                   = DRV_NAME,
> -       .irq_ack                = int0002_irq_ack,
> -       .irq_mask               = int0002_irq_mask,
> -       .irq_unmask             = int0002_irq_unmask,
> -       /*
> -        * No set_wake, on CHT the IRQ is typically shared with the ACPI SCI
> -        * and we don't want to mess with the ACPI SCI irq settings.
> -        */
> -       .flags                  = IRQCHIP_SKIP_SET_WAKE,
> -};
> -
>  static const struct x86_cpu_id int0002_cpu_ids[] = {
>         INTEL_CPU_FAM6(ATOM_SILVERMONT, int0002_byt_irqchip),   /* Valleyview, Bay Trail  */
> -       INTEL_CPU_FAM6(ATOM_AIRMONT, int0002_cht_irqchip),      /* Braswell, Cherry Trail */
> +       INTEL_CPU_FAM6(ATOM_AIRMONT, int0002_byt_irqchip),      /* Braswell, Cherry Trail */
>         {}
>  };
>
> @@ -181,6 +169,10 @@ static int int0002_probe(struct platform_device *pdev)
>         if (!cpu_id)
>                 return -ENODEV;
>
> +       /* We only need to directly deal with PMEs when using s2idle */
> +       if (!pm_suspend_default_s2idle())
> +               return -ENODEV;
> +
>         irq = platform_get_irq(pdev, 0);
>         if (irq < 0)
>                 return irq;
> --
> 2.26.0
>