Ubuntu 21.04, Wayland Session on Gnome 3.38 via Mutter 3.38.4. Dell XPS 13 9300.
I have a USB-C hub which provides power, HID, and HDMI connectivity. Nine times out of ten, when I unplug this dongle, the screen goes black for a while and my user session is reset, presenting me with the login screen. When I log in again, all my open GUI programs have been killed (but background services are still running).
I believe this is due to Mutter (Wayland) crashing, but how can I prevent this?
Sometimes I will see a bunch of @@@@@@@ symbols on a black terminal screen before the login screen is shown.
In dmesg, I find the following:
[435887.627817] Call Trace:
[435887.627823] typec_altmode_update_active+0x60/0x100 [typec]
[435887.627834] ? cancel_work_sync+0x10/0x20
[435887.627842] typec_remove+0xee/0x110 [typec]
[435887.627853] __device_release_driver+0x181/0x240
[435887.627859] device_release_driver+0x29/0x40
[435887.627864] bus_remove_device+0xe1/0x150
[435887.627868] device_del+0x19c/0x3e0
[435887.627873] ? klist_put+0x23/0x90
[435887.627880] device_unregister+0x1b/0x60
[435887.627885] typec_unregister_altmode+0x30/0x40 [typec]
[435887.627896] ucsi_unregister_altmodes+0x46/0xa0 [typec_ucsi]
[435887.627902] ucsi_handle_connector_change+0x2d8/0x510 [typec_ucsi]
[435887.627910] process_one_work+0x220/0x3c0
[435887.627914] worker_thread+0x50/0x370
[435887.627918] kthread+0x12f/0x150
[435887.627923] ? process_one_work+0x3c0/0x3c0
[435887.627926] ? __kthread_bind_mask+0x70/0x70
[435887.627932] ret_from_fork+0x1f/0x30
[435887.627941] ---[ end trace b6d883829019f6e9 ]---
>Solution :
I forgot I had left this one unanswered. I’ve never experienced the issue again after disabling the Ubuntu Dock (which is a shell extension and I learned that these are capable of bringing the whole shell down).
So go to the AppLauncher, and enter "extensions" to open the Extensions panel. Then turn off the Ubuntu dock and learn how to use GNOME without.
Hint: 3-finger trackpad down gets you your applications. Repeat to get to the launcher. Or press the Super key (Windows or otherwise). I don’t miss the dock too much 🙂