Re: [PATCH] pinctrl: intel: Only restore pins that are used by the driver

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Oct 10, 2016 at 3:39 PM, Mika Westerberg
<mika.westerberg@xxxxxxxxxxxxxxx> wrote:

> Dell XPS 13 (and maybe some others) uses a GPIO (CPU_GP_1) during suspend
> to explicitly disable USB touchscreen interrupt. This is done to prevent
> situation where the lid is closed the touchscreen is left functional.
>
> The pinctrl driver (wrongly) assumes it owns all pins which are owned by
> host and not locked down. It is perfectly fine for BIOS to use those pins
> as it is also considered as host in this context.
>
> What happens is that when the lid of Dell XPS 13 is closed, the BIOS
> configures CPU_GP_1 low disabling the touchscreen interrupt. During resume
> we restore all host owned pins to the known state which includes CPU_GP_1
> and this overwrites what the BIOS has programmed there causing the
> touchscreen to fail as no interrupts are reaching the CPU anymore.
>
> Fix this by restoring only those pins we know are explicitly requested by
> the kernel one way or other.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=176361
> Reported-by: AceLan Kao <acelan.kao@xxxxxxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

Patch applied and tagged for stable. Also added Tested-by from
AceLan.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html