Re: [PATCH 5.4 regression fix] Input: soc_button_array - partial revert of support for newer surface devices

[Hans de Goede]

Hi,

On 05-10-2019 14:17, Maximilian Luz wrote:
> Hi,
>
> sorry for the inconvenience this change has caused.
>
> On 10/5/19 12:55 PM, Hans de Goede wrote:
> > Note ideally this seamingly unrelated change would have been made in a
> > separate commit, with a message explaining the what and why of this
> > change.
>
> Would I have known the impact, then yes. This change was added due to
> some reported instances where it seems that soc_button_array would
> occasionally load on MSHW0040 before the GPIO controller was ready,
> causing power and volume buttons to not work.
>
> > I guess this change may have been added to deal with -EPROBE_DEFER errors,
>
> Correct. After a comment mentioned that gpiod_get() returning
> -EPROBE_DEFER would be the proper way to detect this, I decided on this
> change.

Ok, on x86 the GPIO drivers really should all be builtin because
various ACPI methods including device D0 / D3 (power-on/off) methods
may depend on them. So normally this should never happen.

If this (-EPROBE_DEFER on surface devices) somehow still is happening
please let me know and we will figure something out.

> Might I suggest the following addition:
>
> Signed-off-by: Maximilian Luz <luzmaximilian@xxxxxxxxx>

S-o-b is only for patches which pass through your hands, e.g. if
you make changes to my patch and submit a v2 of it.

I guess you mean / want one of:

Acked-by: ...

or

Reviewed-by: ...


?

Regards,

Hans



> ---
>  Âdrivers/input/misc/soc_button_array.c | 25 ++++++++++++++++++++-----
>  Â1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
> index 97e3639e99d0..a0f0c977b790 100644
> --- a/drivers/input/misc/soc_button_array.c
> +++ b/drivers/input/misc/soc_button_array.c
> @@ -92,11 +92,18 @@ soc_button_device_create(struct platform_device *pdev,
>  ÂÂÂÂÂÂÂÂÂÂÂÂ continue;
>
>  ÂÂÂÂÂÂÂÂ gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
> -ÂÂÂÂÂÂÂ if (gpio < 0 && gpio != -ENOENT) {
> -ÂÂÂÂÂÂÂÂÂÂÂ error = gpio;
> -ÂÂÂÂÂÂÂÂÂÂÂ goto err_free_mem;
> -ÂÂÂÂÂÂÂ } else if (!gpio_is_valid(gpio)) {
> -ÂÂÂÂÂÂÂÂÂÂÂ /* Skip GPIO if not present */
> +ÂÂÂÂÂÂÂ if (!gpio_is_valid(gpio)) {
> +ÂÂÂÂÂÂÂÂÂÂÂ /*
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * Skip GPIO if not present. Note we deliberately
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * ignore -EPROBE_DEFER errors here. On some devices
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * Intel is using so called virtual GPIOs which are not
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * GPIOs at all but some way for AML code to check some
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * random status bits without need a custom opregion.
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * In some cases the resources table we parse points to
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * such a virtual GPIO, since these are not real GPIOs
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * we do not have a driver for these so they will never
> +ÂÂÂÂÂÂÂÂÂÂÂÂ * show up, therefor we ignore -EPROBE_DEFER.
> +ÂÂÂÂÂÂÂÂÂÂÂÂ */
>  ÂÂÂÂÂÂÂÂÂÂÂÂ continue;
>  ÂÂÂÂÂÂÂÂ }
>
> @@ -429,6 +436,14 @@ static int soc_device_check_MSHW0040(struct device *dev)
>
>  ÂÂÂÂ dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
>
> +ÂÂÂ /*
> +ÂÂÂÂ * Explicitly check if GPIO controller is ready. This check is done here
> +ÂÂÂÂ * to avoid issues with virtual GPIOs on other chips, as elaborated above.
> +ÂÂÂÂ * We are at least expecting one GPIO pin for the power button (index 0).
> +ÂÂÂÂ */
> +ÂÂÂ if (soc_button_lookup_gpio(dev, 0) == -EPROBE_DEFER)
> +ÂÂÂÂÂÂÂ return -EPROBE_DEFER;
> +
>  ÂÂÂÂ return 0;
>  Â}