Re: [PATCH] Force ELAN06FA touchpad I2C bus freq to 100KHz

R Ha
2025-01-15T19:39:40Z

Hello, and thanks for letting me know.

I'll keep your suggestions in mind the next time I have something to
post. Thanks to everyone for helping debug and get my patch into the
kernel, now I can use my laptop more easily! :)

On Tue, Jan 14, 2025 at 6:58 AM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> On Mon, Jan 13, 2025 at 02:52:37PM -0500, Randolph Ha wrote:
> > When a 400KHz freq is used on this model of ELAN touchpad in Linux,
> > excessive smoothing (similar to when the touchpad's firmware detects
> > a noisy signal) is sometimes applied. As some devices' (e.g, Lenovo
> > V15 G4) ACPI tables specify a 400KHz frequency for this device and
> > some I2C busses (e.g, Designware I2C) default to a 400KHz freq,
> > force the speed to 100KHz as a workaround.
> >
> > For future investigation: This problem may be related to the default
> > HCNT/LCNT values given by some busses' drivers, because they are not
> > specified in the aforementioned devices' ACPI tables, and because
> > the device works without issues on Windows at what is expected to be
> > a 400KHz frequency. The root cause of the issue is not known.
> >
> > Signed-off-by: Randolph Ha <rha051117@gmail.com>
> > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>
> Applied to for-next, thanks!
>
> Some comments for next contributions. Please send new patches always in
> a new thread. It was a bit confusing here to find the latest one.
>
> Also, while the code change looks easy, this is not a trivial change, so
> trivial@ is not appropriate here. Trivial patches are more like typos or
> whitespace fixes.
>
> Nonetheless, thanks again for your efforts in timely debugging this!
>