Bug#922666: confirmed bug report

[Antoine Beaupré <anarcat@debian.org>]

Control: forcemerge 922666 928189
Control: severity 922666 important
Control: tags 922666 +patch +confirmed

I also see a regression with touchpads and trackpoint on a Thinkpad E431
after upgrading from Debian stretch to buster. My research indicates
this is a kernel regression, as yet to be fixed.

This is the result of my research, as available online at:

https://anarc.at/services/upgrades/buster/#touchpad-trackpoint-freeze-after-sleep

On a Thinkpad E431, the entire mouse interface (touch, trackpoint)
freezes after sleep. Keyboard still works but not mouse until a
reboot.

There's [bug 922666][] in Debian buster, without a fix. It also says
it eventually recovers, which is not our experience. Possible dupe is
[bug 928189][].

[bug 928189]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=928189
[bug 922666]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=922666

There's also [bug 1791427][] in Ubuntu 18.04 that seems related, and
which proposes the following workarounds:

 * In gsettings: `org.gnome.desktop.peripherals.touchpad click-method disabled`

 * A .service file:

        # /etc/systemd/system/touchpad-sleep.service
        # restore touchpad on suspend

        [Unit]
        Description=Restore Touchpad on suspend
        Before=sleep.target
        StopWhenUnneeded=yes

        [Service]
        #Type=oneshot
        Type=idle
        RemainAfterExit=yes
        ExecStart=/bin/bash -c 'echo "0000:00:1f.4" > /sys/bus/pci/drivers/i801_smbus/unbind'
        ExecStop=/bin/bash -c 'echo "0000:00:1f.4" > /sys/bus/pci/drivers/i801_smbus/bind'

        [Install]
        WantedBy=sleep.target

 * "Maybe try xserver-xorg-input-evdev instead of xserver-xorg-input-libinput?"

 * reloading `psmouse`:
 
        sudo modprobe -r psmouse
        sudo modprobe psmouse

 * "`modprobe i2c-i801` after removing it from the `blacklist.conf` seems to solve the issue."

 * whatever this is:
 
        # echo 1 > /sys/devices/rmi4-00/nosleep

 * "Anyone who still affected by touchpad issues after S3. Please
   switch back to suspend-to-idle in BIOS if s2idle is
   supported. ThinkPad Carbon 6th and Yoga 3rd do support
   suspend-to-idle in BIOS->config->power menu."

[bug 1791427]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1791427

There's also [bug 1442699][] in Fedora, which suggests those
workarounds:

 * another module reload:
 
        sudo rmmod i2c_hid
        sudo modprobe i2c_hid

 * "Just updated to kernel-4.12.5-300.fc26.x86_64 in updates-testing
   and this issue seems to have been resolved (for me)."

 * another `/proc` hack:
 
        echo -n "reconnect" >  /sys/bus/serio/devices/serio1/drvctl

 * "The `psmouse.synaptics_intertouch=0` workaround still works for me."

[bug 1442699]: https://bugzilla.redhat.com/show_bug.cgi?id=1442699

Also related is this [libinput bug][] that's closed as "not our bug"
because they claim it's a bug in the kernel.

[libinput bug]: https://bugs.freedesktop.org/show_bug.cgi?id=103149

There are [two][] [patches][] on the Linux kernel which apparently fix the
issue, still pending approval:

[two]: https://lkml.org/lkml/2019/2/20/700
[patches]: https://lkml.org/lkml/2019/2/20/701

Possibly related: https://lkml.org/lkml/2016/8/18/134

[5.1rc7][] shipped two fixes against the `synaptics-rmi4` module. A
[pull request][] has been merged in mainline with two other fixes on
the module./ [5.0.11][] also has fixes on the module. It's clearly a
regression from Debian stretch (kernel 4.9) since it was working fine
before.

Possibly related, [two-finger scrolling bug in Ubuntu][], which
identifies [this commit][] as the source of the regression. [Upstream
kernel bug][], still open.

[5.1rc7]: https://lkml.org/lkml/2019/4/28/270
[pull request]: https://lkml.org/lkml/2019/7/12/19
[5.0.11]: https://lkml.org/lkml/2019/5/2/287
[Upstream kernel bug]: https://bugzilla.kernel.org/show_bug.cgi?id=196719
[this commit]: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e839ffab028981ac77f650faf8c84f16e1719738
[two-finger scrolling bug in Ubuntu]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1722478

I haven't tried any of those workarounds. I hope this helps!

-- 
Si les triangles avaient un Dieu, ils lui donneraient trois côtés.
                        - Montesquieu, Lettres persanes