Black screen with blinking cursor

[Luis Alberto Pabón]

For some reason, since today GDM has ceased to work. No updates came through as last time I installed any updates was a week ago.

Upon boot, gdm goes to a black screen with a cursor. This screen flickers to show the underlying tty and on each flicker the cursor position resets.

I can start my window manager (sway) without issue from the console still and everything functions normally.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gdm3 3.36.3-0ubuntu0.20.04.2
ProcVersionSignature: Ubuntu 5.4.0-53.59-generic 5.4.65
Uname: Linux 5.4.0-53-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: sway
Date: Fri Dec 18 13:44:09 2020
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

[Luis Alberto Pabón (copong)]

Just to point out I have power-cycled my laptop in case a reboot wasn't cutting it.

Also, I can switch TTY no problem, that's how I'm starting the window manager.

[Luis Alberto Pabón (copong)]

If I leave GDM3 like that for a while (around 30 secs or so) it will eventually terminate and drop to the underlying tty.

Conversely, lightdm is working correctly. I can use that for the time being.

[Daniel van Vugt (vanvugt)]

You appear to have the 'oibaf' PPA installed which commonly causes graphics problems, and might be the problem here too.

To remove all doubt, please uninstall that PPA using the 'ppa-purge' tool. Then if you experience any more problems please open new bugs for them.

[Luis Alberto Pabón (copong)]

Thank you Daniel. I needed oibaf's updates to get ahold of Mesa <=20.2 and libgnvd <=1.3.2 in order to successfully compile wlroots and sway from sources.

Now that hwe has come out with the updates I needed I ppa-purged oibaf, but the issue remains.

I have re-opened this on https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1910559