Bug#976366: Upgrade to 247 broke keyboard input on Wayland session

[Marc Dequènes (duck)]

Package: systemd
Version: 247.1-3
Severity: critical
Justification: breaks graphical session input
Control: affects -1 sway


Quack,

After upgrade from 246.6-5 to 247.1-3 I experienced impossibility to use 
my keyboard after login on graphical session.

I'm using Lightdm + Sway and could input with my usual keyboard for 
encrypted disk passphrase, GRUB, and lightdm login screen too. Console 
also was working fine. But after login on lightdm I could not input 
anything in Sway while the mouse worked fine (but I could not do much).

I was able to capture this error in sway log:
00:00:00.142 [ERROR] [backend/session/logind.c:75] Failed to take device 
'/dev/input/event5': No such device
00:00:00.143 [ERROR] [backend/session/logind.c:75] Failed to take device 
'/dev/input/event6': No such device

These files existed and were using the usual root:input rw/rw/- 
permissions. These are devices for my keyboard and LightDM X session 
enumerates them properly:
[    31.282] (II) config/udev: Adding input device ckb1: Corsair Gaming 
K70 LUX RGB Keyboard vKB (/dev/input/event5)
[    31.282] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: 
Applying InputClass "evdev pointer catchall"
[    31.282] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: 
Applying InputClass "evdev keyboard catchall"
[    31.282] (II) Using input driver 'evdev' for 'ckb1: Corsair Gaming 
K70 LUX RGB Keyboard vKB'
[    31.282] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: always 
reports core events
[    31.282] (**) Option "config_info" 
"udev:/sys/devices/virtual/input/input27/event5"
[    31.282] (II) XINPUT: Adding extended input device "ckb1: Corsair 
Gaming K70 LUX RGB Keyboard vKB" (type: KEYBOARD, id 12)
[    31.282] (**) Option "xkb_rules" "evdev"
[    31.282] (**) Option "xkb_model" "pc105"
[    31.282] (**) Option "xkb_layout" "us"
[    31.282] (**) Option "xkb_variant" "altgr-intl"
[    31.282] (**) Option "xkb_options" "compose:menu,level3:ralt_switch"
[    31.283] (II) evdev: ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: 
initialized for relative axes.
[    31.283] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: (accel) 
keeping acceleration scheme 1
[    31.283] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: (accel) 
acceleration profile 0
[    31.283] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: (accel) 
acceleration factor: 2.000
[    31.283] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vKB: (accel) 
acceleration threshold: 4
[    31.284] (II) config/udev: Adding input device ckb1: Corsair Gaming 
K70 LUX RGB Keyboard vM (/dev/input/event6)
[    31.284] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vM: Applying 
InputClass "evdev pointer catchall"
[    31.284] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vM: Applying 
InputClass "evdev keyboard catchall"
[    31.284] (II) Using input driver 'evdev' for 'ckb1: Corsair Gaming 
K70 LUX RGB Keyboard vM'
[    31.284] (**) ckb1: Corsair Gaming K70 LUX RGB Keyboard vM: always 
reports core events
[    31.284] (**) evdev: ckb1: Corsair Gaming K70 LUX RGB Keyboard vM: 
Device: "/dev/input/event6"
[    31.284] (--) evdev: ckb1: Corsair Gaming K70 LUX RGB Keyboard vM: 
Vendor 0x1b1c Product 0x1b33
[    31.284] (**) Option "config_info" 
"udev:/sys/devices/virtual/input/input28/event6"
[    31.284] (II) XINPUT: Adding extended input device "ckb1: Corsair 
Gaming K70 LUX RGB Keyboard vM" (type: KEYBOARD, id 13)

My /etc/systemd/logind.conf is unaltered from the default.

I did not find any apparmor denial.

I could not find anything meaningful in systemd logs or others. Then I 
checked what packages were upgraded recently and gave it a try 
downgrading to 246.6-5, and after a reboot it worked. Tell me if I can 
provide any other information.

Regards.
\_o<

-- 
Marc Dequènes