Re: [PATCH v2 2/2] HID: Make elan touch controllers power on after panel is enabled

[Doug Anderson]

Hi,

On Wed, Aug 13, 2025 at 5:51 AM Pin-yen Lin <treapking@xxxxxxxxxxxx> wrote:
>
> Introduce a new HID quirk to indicate that this device has to be enabled
> after the panel's backlight is enabled, and update the driver data for
> the elan devices to enable this quirk. This cannot be a I2C HID quirk
> because the kernel needs to acknowledge this before powering up the
> device and read the VID/PID. When this quirk is enabled, register
> .panel_enabled()/.panel_disabling() instead for the panel follower.
>
> Also rename the *panel_prepare* functions into *panel_follower* because
> they could be called in other situations now.
>
> Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
>
> ---
>
> Changes in v2:
> - Rename *panel_prepare* functions to *panel_follower*
> - Replace after_panel_enabled flag with enabled/disabling callbacks
>
>  drivers/hid/i2c-hid/i2c-hid-core.c    | 46 ++++++++++++++++-----------
>  drivers/hid/i2c-hid/i2c-hid-of-elan.c | 11 ++++++-
>  include/linux/hid.h                   |  2 ++
>  3 files changed, 40 insertions(+), 19 deletions(-)

This seems reasonable to me.

Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>

Given that this affects devices that we already had support for
(you're changing the behavior of two touchscreens), should it have a
Fixes tag?

We'll also need to figure out a process for landing the two patches. I
can easily land the first one in drm-misc-next, but then it'll be a
while before the i2c-hid one can land. Is it OK to wait?


-Doug