Created attachment 143301 [details] dmesg log I'm using Arch Linux with Linux 4.20.6, X11 and the modesetting driver together with the KDE plasma desktop (5.14.5). After using the desktop for a while (in particular, after causing some graphics load) visual artifacts appear and plasma-desktop often hangs up. Sometimes the hanging process can be restarted, other times X is completely frozen (but can still be ssh'ed into). The dmesg log shows these lines, although only the fifo DMA_PUSHER lines seem to consistently appear every time the problem is triggered: [ 227.576711] nouveau 0000:04:00.0: fifo: DMA_PUSHER - ch 6 [Xorg[751]] get 00000eb764 put 00000ec8ec ib_get 00000167 ib_put 0000016a state 80006eac (err: INVALID_CMD) push 00400040 [ 227.630897] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630904] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 1348 data 00046da0 [ 227.630916] nouveau 0000:04:00.0: fifo: DMA_PUSHER - ch 6 [Xorg[751]] get 00000fcb8c put 0000102f84 ib_get 00000178 ib_put 0000017c state 80007354 (err: INVALID_CMD) push 00400040 [ 227.630926] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630929] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 134c data 00000000 [ 227.630938] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630941] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 1350 data 000479d0 [ 227.630950] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630953] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 1348 data 00046da0 [ 227.630964] nouveau 0000:04:00.0: fifo: DMA_PUSHER - ch 6 [Xorg[751]] get 00000fcb8c put 0000102f84 ib_get 0000017a ib_put 0000017c state 80007354 (err: INVALID_CMD) push 00400040 [ 227.630975] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630978] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 134c data 00000000 [ 227.630988] nouveau 0000:04:00.0: gr: DATA_ERROR 00000005 [INVALID_ENUM] [ 227.630991] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 1350 data 000479d0 [ 227.665017] nouveau 0000:04:00.0: gr: DATA_ERROR 0000000c [INVALID_BITFIELD] [ 227.665022] nouveau 0000:04:00.0: gr: 00100000 [] ch 6 [007f437000 Xorg[751]] subc 3 class 8397 mthd 135c data 000472e8 [ 227.847944] nouveau 0000:04:00.0: fifo: DMA_PUSHER - ch 6 [Xorg[751]] get 0000138e10 put 000013b454 ib_get 000001ad ib_put 000001b0 state 40000004 (err: INVALID_MTHD) push 00400040 [ 227.850171] nouveau 0000:04:00.0: fifo: CACHE_ERROR - ch 6 [Xorg[751]] subc 0 mthd 0000 data 00146200 [ 227.889579] nouveau 0000:04:00.0: Xorg[751]: multiple instances of buffer 4 on validation list [ 227.889588] nouveau 0000:04:00.0: Xorg[751]: validate_init [ 227.889590] nouveau 0000:04:00.0: Xorg[751]: validate: -22 [ 227.891472] nouveau 0000:04:00.0: fifo: DMA_PUSHER - ch 6 [Xorg[751]] get 0000141bf0 put 00001479b8 ib_get 000001b4 ib_put 000001b5 state 80007418 (err: INVALID_CMD) push 00400040 (the full dmesg.log is attached) This problem is rather new. It was introduced with a package upgrade in Arch Linux that happened within the last few days (I will attach the pacman upgrade log for those who want to know.)
Created attachment 143302 [details] pacman upgrade log
Managed to pin down the problem to the upgrade of qt5 from 5.12.0 to 5.12.1. I don't know how that upgrade can cause the bug, but problems go away when downgrading again.
*** Bug 109558 has been marked as a duplicate of this bug. ***
I bisected the problem to a commit in Qt 5.12.1 which enabled multithreaded GL rendering. I've read elsewhere that nouveau DRM doesn't deal well with mt rendering. For more info, see here: https://bugreports.qt.io/browse/QTBUG-73715 So from the nouveau side there's no new problem here and I think this bug report can be closed.
(In reply to qjztreez from comment #3) > *** Bug 109558 has been marked as a duplicate of this bug. *** Are you using the oxygen theme? If yes, please checkout https://bugreports.qt.io/browse/QTBUG-73691 which is not the same problem as mine.
(In reply to bastian.beischer from comment #5) > (In reply to qjztreez from comment #3) > > *** Bug 109558 has been marked as a duplicate of this bug. *** > > Are you using the oxygen theme? If yes, please checkout > > https://bugreports.qt.io/browse/QTBUG-73691 > > which is not the same problem as mine. No, I am using Arc KDE theme with Kvantum, and I forgot to mention that either downgrading Qt to 5.12.0 or installing the proprietary NVIDIA driver seemed to solve my problem.
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