Locking screen crashes X/Wayland with nouveau when multiple monitors are plugged in

[Brock York]

Trying to run Ubuntu 20.04 on some Dell workstations with Nvidia Quadro P2200 cards. Getting some odd crashes. If a single monitor is plugged and the workstation is power on you can then log in and plug a second monitor in and locking the screen DOES not crash X/Wayland/nouveau. If you boot the system with both monitors plugged in then logging in and locking the computer will cause X/Wayland/Nouveau to crash and only a reboot will fix it. You can still ssh into the box though. The monitors are connected via DisplayPort.

There were no kernel backtraces in the journal when running this bug report. But in other cases there has been nouveau backtraces.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.8.0-59-generic 5.8.0-59.66~20.04.1
ProcVersionSignature: Ubuntu 5.8.0-59.66~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-59-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: skip
Date: Fri Jun 25 16:02:35 2021
InstallationDate: Installed on 2021-06-25 (0 days ago)
InstallationMedia: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
SourcePackage: linux-signed-hwe-5.8
UpgradeStatus: No upgrade log present (probably fresh install)

[Brock York (twunknown)]

This journal log contains the nouveau backtrace after locking the computer

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tony Beaumont (a-j-beaumont)]

I am seeing a similar issue with a second monitor plugged in. I am using nouveau and it crashes the X server and logs me out. I have attached a log of what happened. This is NOT connected with a screen lock, it happens randomly.

Display is:
  *-display
       description: VGA compatible controller
       product: GK107GLM [Quadro K1100M]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nouveau latency=0
       resources: irq:37 memory:d1000000-d1ffffff memory:70000000-7fffffff memory:80000000-81ffffff ioport:5000(size=128) memory:c0000-dffff

[Brock York (twunknown)]

Problem seems to be fixed now. Not sure at what point it stopped being broken but the problem is no longer exhibited on Ubuntu 20.04.3 on a 5.11.0-41-generic kernel with Nouveau xserver-xorg-video-nouveau 1:1.0.16-1 with Gnome 1:3.30+2 and GDM3 3.36.3-0ubuntu.20.04.4 using X11 not wayland.