Regression in Elan Touchpad driver / Linux 5.12

Hello,

since migrating to Linux 5.12, the Elan touchpad stopped working for
me. I created a bug report on
https://bugzilla.kernel.org/show_bug.cgi?id=213093
2but I am not sure whether that reached anyone here.

The symptom is that when running 5.12, the touchpad does not show up.

I tested so far with 5.12.3, 5.12.4 and 5.12.6, all behave the same,
latest dmesg output on 5.12.6 does not show the touchpad driver loading,
only the one for the trackpoint:

[13:35] nb3:~% dmesg| grep -i elan
[   11.845386] psmouse serio1: trackpoint: Elan TrackPoint firmware: 0x62, buttons: 3/3
[   11.857853] input: TPPS/2 Elan TrackPoint as /devices/platform/i8042/serio1/input/input23
[13:35] nb3:~%

The hardware I am using is an Lenovo X1 nano, however other people also
reported this problem before.

If there is anything I can do to debug this, any pointer would be
appreciated.

Best regards,

Nico

--
Sustainable and modern Infrastructures by ungleich.ch

Hi,

On Mon, May 24, 2021 at 01:38:06PM +0200, Nico Schottelius wrote:

Hello,

since migrating to Linux 5.12, the Elan touchpad stopped working for
me. I created a bug report on
https://bugzilla.kernel.org/show_bug.cgi?id=213093
2but I am not sure whether that reached anyone here.

The symptom is that when running 5.12, the touchpad does not show up.

I tested so far with 5.12.3, 5.12.4 and 5.12.6, all behave the same,
latest dmesg output on 5.12.6 does not show the touchpad driver loading,
only the one for the trackpoint:

[13:35] nb3:~% dmesg| grep -i elan
[   11.845386] psmouse serio1: trackpoint: Elan TrackPoint firmware: 0x62, buttons: 3/3
[   11.857853] input: TPPS/2 Elan TrackPoint as /devices/platform/i8042/serio1/input/input23
[13:35] nb3:~%

The hardware I am using is an Lenovo X1 nano, however other people also
reported this problem before.

If there is anything I can do to debug this, any pointer would be
appreciated.

Do you have i2c-hid-acpi module enabled?

Thanks.

-- 
Dmitry

Dmitry Torokhov [off-list ref] writes:

quoted

If there is anything I can do to debug this, any pointer would be
appreciated.

Do you have i2c-hid-acpi module enabled?

I just rebuild 5.12.6 with i2c-hid-acpi and it works again. Thanks a lot
for the pointer. I also notified the Alpine Linux team to include in
kernels >= 5.12.

Thanks again and have a good evening!

Nico

--
Sustainable and modern Infrastructures by ungleich.ch