regression: nouveau fifo: fault 01 ==> channel 1: killed ==> dead desktop

[Mike Galbraith]

When the below new to 5.11 cycle badness happens, it's time to reboot.

...
[   27.467260] NFSD: Using UMH upcall client tracking operations.
[   27.467273] NFSD: starting 90-second grace period (net f00000a0)
[   27.965138] Bridge firewalling registered
[   39.096604] fuse: init (API version 7.32)
[  961.579832] nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 000000000069f000 engine 15 [CE0] client 01 [HUB/CE0] reason 02 [PTE] on channel 1 [00ff73d000 DRM]
[  961.579840] nouveau 0000:01:00.0: fifo: channel 1: killed
[  961.579844] nouveau 0000:01:00.0: fifo: runlist 0: scheduled for recovery
[  961.579850] nouveau 0000:01:00.0: fifo: runlist 4: scheduled for recovery
[  961.579853] nouveau 0000:01:00.0: fifo: engine 4: scheduled for recovery

Box is aging generic i4790 desktop box with...
01:00.0 VGA compatible controller: NVIDIA Corporation GM204 [GeForce GTX 980] (rev a1)

	-Mike