Re: Elantech touchpad not working on mainline kernels

On Wed, 2021-07-21 at 10:48 -0700, Dmitry Torokhov wrote:

Hi Hans,

On Sun, May 30, 2021 at 2:12 AM Hans Schultz <
hans.schultz@webspeed.dk> wrote:

quoted

Hello,
I have a problem getting my Elantech touchpad to work with the
mainline
kernels, and I need some assistance with the code to resolve the
problem.
The kernels that have tried are 5.9.11 and 5.11.11.

With boot parameters i8042.notimeout i8042.nomux, the touchpad is
detected but does not work. There is absolutely no response from it
with any hid modules loaded.

It is reported and seen working on a Lubuntu distro (bionic kernel)
when inserting the i2c_hid module. The insertion of the i2c_hid
module
pulls in the hid_multitouch module when it works, no boot parameters
necessary.
In the case where it does not work, insering the i2c_hid module does
not pull in the hid_multitouch module.

I have the bionic kernel code, but I have not as of yet been able to
detect what makes it work in contrast to the kernel.org kernels.

This I think should lead to a kernel patch.

There is not much to go on with. What is the hardware, your kernel
.config, dmesg from unsuccessful boot? If you have logs from the
working kernel that would help too.

Thanks.

The best info I have on the hardware is from Xorg log with the working
Lubuntu kernel:
[ 130.980] (II) Loading /usr/lib/xorg/modules/input/synaptics_drv.so
[ 130.982] (II) Module synaptics: vendor="X.Org Foundation"
[ 130.982] (II) Using input driver 'synaptics' for '0X45 0X4C 0X41 0:00
04F3:308C Touchpad'

I might be able to get the kernel messages when inserting the working
module, but I think it will not tell much more.
To me it is clearly a code issue as the working kernel pulls in
hid_multitouch when inserting i2c_hid, while the non-working does not.

All kernels I have tried up to now from kernel.org do not work. The
latest being 5.13.4.