kern/60202: nouveau fifo channel killed, xorg server dies

["nia%pkgsrc.org@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60202
>Category:       kern
>Synopsis:       nouveau fifo channel killed, xorg server dies
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 21 10:00:00 +0000 2026
>Originator:     nia
>Release:        current, netbsd-11, netbsd-10
>Organization:
The NetBSD Foundation
>Environment:
NetBSD siphon 11.99.5 NetBSD 11.99.5 (SIPHON) #1: Fri Mar 27 23:08:51 CET 2026  nia@siphon:/encrypt/obj/sys/arch/amd64/compile/SIPHON amd64
>Description:
After running an OpenGL application, the X server dies, and the following
appears in dmesg:

nouveau0: autoconfiguration error: error: fifo: fault 00 [READ] at 0000000007513000 engine 1b [CE2] client 18 [HUB/GR_CE] reason 02 [PTE] on channel 2 [007fb82000 user]
nouveau0: notice: fifo: channel 2: killed
nouveau0: notice: fifo: runlist 0: scheduled for recovery
nouveau0: notice: fifo: engine 6: scheduled for recovery
nouveau0: warn: user: channel 2 killed!

This renders the machine unable to have a stable X session until it
is rebooted. Afterwards, X keeps dying very frequently.
>How-To-Repeat:
Run games/xonotic, open the settings menu, change resolution, switch
from fullscreen, exit it.
>Fix:
userconf disable nouveau