Re: Any other ways to debug GPIO interrupt controller (pinctrl-amd) for broken touchpads of a new laptop model?

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Tue, Oct 6, 2020 at 10:32 AM Coiby Xu <coiby.xu@xxxxxxxxx> wrote:

> Disabling the glitch filter works like a charm! Other enthusiastic
> Linux users who have been troubled by this issue for months would
> also feel great to know this small tweaking could bring their
> touchpad back to life:) Thank you!

Oh you found the bug :D

> $ git diff
> diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
> index 9a760f5cd7ed..e786d779d6c8 100644
> --- a/drivers/pinctrl/pinctrl-amd.c
> +++ b/drivers/pinctrl/pinctrl-amd.c
> @@ -463,7 +463,7 @@ static int amd_gpio_irq_set_type(struct irq_data *d, unsigned int type)
>                  pin_reg &= ~(ACTIVE_LEVEL_MASK << ACTIVE_LEVEL_OFF);
>                  pin_reg |= ACTIVE_LOW << ACTIVE_LEVEL_OFF;
>                  pin_reg &= ~(DB_CNTRl_MASK << DB_CNTRL_OFF);
> -               pin_reg |= DB_TYPE_PRESERVE_HIGH_GLITCH << DB_CNTRL_OFF;
> +               /** pin_reg |= DB_TYPE_PRESERVE_HIGH_GLITCH << DB_CNTRL_OFF; */
>                  irq_set_handler_locked(d, handle_level_irq);
>                  break;
>
> I will learn more about the glitch filter and the implementation of
> pinctrl and see if I can disable glitch filter only for this touchpad.

Yes we certainly need a quirk for this of some kind, examine the ACPI
quirk infrastructure in drivers/gpio/gpiolib-acpi.c to see if you can use
that to handle this.

Yours,
Linus Walleij