linux-kernel - Re: [PATCH v6] ACPI: skip IRQ override on AMD Zen platforms

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Date:   Thu, 14 Jul 2022 20:35:39 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Chuanhong Guo <gch981213@...il.com>
Cc:     ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Tighe Donnelly <tighe.donnelly@...tonmail.com>,
        Mario Limonciello <mario.limonciello@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6] ACPI: skip IRQ override on AMD Zen platforms

On Tue, Jul 12, 2022 at 4:01 AM Chuanhong Guo <gch981213@...il.com> wrote:
>
> IRQ override isn't needed on modern AMD Zen systems.
> There's an active low keyboard IRQ on AMD Ryzen 6000 and it will stay
> this way on newer platforms. This IRQ override breaks keyboards for
> almost all Ryzen 6000 laptops currently on the market.
>
> Skip this IRQ override for all AMD Zen platforms because this IRQ
> override is supposed to be a workaround for buggy ACPI DSDT and we can't
> have a long list of all future AMD CPUs/Laptops in the kernel code.
> If a device with buggy ACPI DSDT shows up, a separated list containing
> just them should be created.
>
> Suggested-by: Mario Limonciello <mario.limonciello@....com>
> Signed-off-by: Chuanhong Guo <gch981213@...il.com>

I need an ACK from Mario here.

> ---
> Change sice v5: reworked
>
>  drivers/acpi/resource.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> index c2d494784425..510cdec375c4 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -416,6 +416,16 @@ static bool acpi_dev_irq_override(u32 gsi, u8 triggering, u8 polarity,
>  {
>         int i;
>
> +#ifdef CONFIG_X86
> +       /*
> +        * IRQ override isn't needed on modern AMD Zen systems and
> +        * this override breaks active low IRQs on AMD Ryzen 6000 and
> +        * newer systems. Skip it.
> +        */
> +       if (boot_cpu_has(X86_FEATURE_ZEN))
> +               return false;
> +#endif
> +
>         for (i = 0; i < ARRAY_SIZE(skip_override_table); i++) {
>                 const struct irq_override_cmp *entry = &skip_override_table[i];
>
> --
> 2.36.1
>