On Wed, Nov 25, 2020 at 2:03 PM Coiby Xu <coiby.xu@xxxxxxxxx> wrote:
> Debounce filter setting should be independent from IRQ type setting
> because according to the ACPI specs, there are separate arguments for
> specifying debounce timeout and IRQ type in GpioIo() and GpioInt().
>
> Together with commit 06abe8291bc31839950f7d0362d9979edc88a666
> ("pinctrl: amd: fix incorrect way to disable debounce filter") and
> Andy's patch "gpiolib: acpi: Take into account debounce settings" [1],
> this will fix broken touchpads for laptops whose BIOS set the
> debounce timeout to a relatively large value. For example, the BIOS
> of Lenovo AMD gaming laptops including Legion-5 15ARH05 (R7000),
> Legion-5P (R7000P) and IdeaPad Gaming 3 15ARH05, set the debounce
> timeout to 124.8ms. This led to the kernel receiving only ~7 HID
> reports per second from the Synaptics touchpad
> (MSFT0001:00 06CB:7F28).
>
> Existing touchpads like [2][3] are not troubled by this bug because
> the debounce timeout has been set to 0 by the BIOS before enabling
> the debounce filter in setting IRQ type.
>
> [1] https://lore.kernel.org/linux-gpio/20201111222008.39993-11-andriy.shevchenko@xxxxxxxxxxxxxxx/
> [2] https://github.com/Syniurge/i2c-amd-mp2/issues/11#issuecomment-721331582
> [3] https://forum.manjaro.org/t/random-short-touchpad-freezes/30832/28
>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Cc: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1887190
> Link: https://lore.kernel.org/linux-gpio/CAHp75VcwiGREBUJ0A06EEw-SyabqYsp%2Bdqs2DpSrhaY-2GVdAA%40mail.gmail.com/
> Signed-off-by: Coiby Xu <coiby.xu@xxxxxxxxx>
> ---
> Changelog v4:
> - Note in the commit message that this patch depends on other two
> patches to fix the broken touchpad [Hans de Goede]
> - Add in the commit message that one more touchpad could be fixed.
Patch applied for fixes adding a reference to Andy's commit.
Thanks for sorting this out!
Yours,
Linus Walleij
