Touchpad and Pen devices lost in update from 22.02.2 to 22.04.3

[Günther Diederich]

Edit 2023-08-12: Bug not solved but able to reattach touchscreen und pen, corrected typo in title 5.1.2

TLDR: If the wacom module is available, get the device for touchscreen and pen from dmesg, e.g. "ttyS4" and reattach it using "sudo inputattach --daemon --w8001 /dev/ttyS4". A persistent solution would be better, suppposedly an udev rule, but I can't provide that. Version number in title of 5.1.2 is now correctly "22.04.03".

Workaround to reattach touchscreen und pen
Please note: I am new to this and don't know about etiquette in bug reports or how device handling works, so the workaround is not persistent and may be even obvious, but I hope mentioning it here rather helps than hurts handling the bug.
I stumpled upon https://bugzilla.redhat.com/show_bug.cgi?id=1046912, especially about the inputattach command that Putzi81 (entry from 2013-12-27 11:29:25 UTC) tried. Unfortunately it didn't work out for Putzi81 but it did work for me, so step by step:
1) First, check if:
- wacom module is available
-- e.g.: sudo lsmod | grep -i wacom results in a least one line starting with "wacom_w8001"
- Touchscreen and pen are listed in dmesg
-- e.g.: sudo dmesg | grep -i wacom (see also below 5.1.2)
2) Reattach touchscreen and pen
- find ttyS in result of dmesg
-- example: in 5.1.2 the result of dmesg contains "as /devices/pnp0/00:05/tty/ttyS4/" so "ttyS4" is what you'll need to proceed
- add ttyS at the end of "sudo inputattach --daemon --w8001 /dev/ttyS4
--- continuing the example above: "sudo inputattach --daemon --w8001 /dev/ttyS4"
- touchscreen and pen should be working now, maybe you need to configure them under system preferences
3) Further notes
TLDR: Two open questions are "How to get the inputattach to be permanent?" and "Should the workaround inputattach include the option --baud 38400?". Udev rules exist but do not seem to be working as intended.
So this is how far I got:
The result of inputattach is not persistent, permament devices should be attachted at startup. As far as I understood, udev rules should attach the wacom devices at startup. There is a file with wacom related inputattach rules for udev on my system, but it doesn't work:
/lib/udev/rules.d/60-inputattach.rules
# Attach Wacom W8001 devices
SUBSYSTEM=="tty", KERNEL=="ttyS[0-9]*", ATTRS{id}=="FUJ02e5", ACTION=="add|change", RUN+="/usr/bin/inputattach --daemon --baud 19200 --w8001 /dev/%k"
SUBSYSTEM=="tty", KERNEL=="ttyS[0-9]*", ATTRS{id}=="WACf00c", ACTION=="add|change", RUN+="/usr/bin/inputattach --daemon --baud 38400 --w8001 /dev/%k"
The last line should result in the same inputattach command from the workaround, except for the baud rate. The id "WACf00c" seems to be correct, as it is the id of parent device to ttyS4 listed via sudo udevadm info -a -n /dev/ttyS4. Compared to the workaround, the additional "--baud 38400" doesn't change the result, the manual inputattach of the workaround works with and without it.
There are no wacom-related files unter /etc/udev/rules.d, but two more under /lib/udev/rules.d, but they are beyond me:
65-libwacom.rules
69-wacom.rules
I don't know if I'll able to contribute anything more to this, so thanks to everyone out there caring about the bug!
-- End of edit

1) Release of Ubuntu
Description: Ubuntu 22.04.3 LTS
Release: 22.04

Edit 2023-08-11: Added following information about my system
- Hardware Model: Lenovo ThinkPad X201 Tablet
- Windowing System: Wayland
-- used under 22.04.2 and 22.04.3
- OS Type 64-bit
- GNOME Version 42.9
- No proprietary drivers are in use
- Touchpad and trackpen working before and after update
- Additional buttons (e.g. screen rotation) working before and after update

2) version of package used
unknown

Additional information
- "linux-signed-hwe-6.2" was chosen, when I used the link https://launchpad.net/ubuntu/+source/linux (see 5)
- opted for unknown, because I wasn't sure about that

3) What did I expect to happen
3.1) What I did
- Fresh install Ubuntu 22.04.2 LTS on Lenovo X201 Tablet
-- Status: Touchscreen and pen working, shown and configurable in system settings as Wacom (additional information see below)
- Software Updater used to update from 22.04.2 to 22.04.3
3.2) What I expected
- Expected Touchscreen and pen continue to work

4) What happened instead
- Touchscreen and pen stopped working
- Wacom not listed in system settings anymore

5) Additional information

I have been following instructions from https://wiki.ubuntu.com/DebuggingTouchpadDetection, seemed to be applicable to my problem, too:

- Executed sudo cat /proc/bus/input/devices under 22.04.3 (result see below 5.2)
- Didn't see Wacom touchscreen or pen
- Followed recommendation to file a bug report using link https://launchpad.net/ubuntu/+source/linux

Additional preparation: Reinstall 22.04.2 LTS, getting dmesg and device list for comparison

5.1) dmesg | grep -i wacom

5.1.1) 22.04.2 (before update)

[ 7.629695] input: Wacom Serial Penabled 2FG Touchscreen Pen as /devices/pnp0/00:05/tty/ttyS4/serio3/input/input9
[ 7.633934] input: Wacom Serial Penabled 2FG Touchscreen Finger as /devices/pnp0/00:05/tty/ttyS4/serio3/input/input10
[ 26.705762] input: Wacom Serial Penabled 2FG Touchscreen Pen as /devices/pnp0/00:05/tty/ttyS4/serio4/input/input17
[ 26.706089] input: Wacom Serial Penabled 2FG Touchscreen Finger as /devices/pnp0/00:05/tty/ttyS4/serio4/input/input18

5.1.2) 22.04.3 (after update)

[ 8.018162] input: Wacom Serial Penabled 2FG Touchscreen Pen as /devices/pnp0/00:05/tty/ttyS4/serio3/input/input9
[ 8.018535] input: Wacom Serial Penabled 2FG Touchscreen Finger as /devices/pnp0/00:05/tty/ttyS4/serio3/input/input10

5.2) Device list 22.04.3 does not contain the following entries from 22.04.2

Device: Wacom Serial Penabled 2FG Touchscreen Pen
Kernel: /dev/input/event9
Group: 10
Seat: seat0, default
Size: 263x165mm
Capabilities: tablet
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: identity matrix
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Accel profiles: none
Rotation: n/a

Device: Wacom Serial Penabled 2FG Touchscreen Finger
Kernel: /dev/input/event10
Group: 10
Seat: seat0, default
Size: 263x165mm
Capabilities: touch
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: n/a
Nat.scrolling: n/a
Middle emulation: n/a
Calibration: identity matrix
Scroll methods: none
Click methods: none
Disable-w-typing: n/a
Accel profiles: n/a
Rotation: n/a

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-6.2.0-26-generic 6.2.0-26.26~22.04.1
ProcVersionSignature: Ubuntu 6.2.0-26.26~22.04.1-generic 6.2.13
Uname: Linux 6.2.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Fri Aug 11 12:10:53 2023
InstallationDate: Installed on 2023-08-11 (0 days ago)
InstallationMedia: Ubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64 (20230223)
SourcePackage: linux-signed-hwe-6.2
UpgradeStatus: No upgrade log present (probably fresh install)