Re: [PATCH v4] pinctrl: amd: remove debounce filter setting in IRQ type setting

From: Coiby Xu
Date: Fri Dec 04 2020 - 07:39:40 EST


On Fri, Dec 04, 2020 at 10:03:43AM +0100, Linus Walleij wrote:
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!


Thank you for applying the patch!

Yours,
Linus Walleij

--
Best regards,
Coiby