Comment 21 for bug 1723758

Xorg hangs randomly with nouveau driver. It could be reproduced cometimes when playing video or starting libreoffice, but not limited to. If pressing Ctrl+Alt+Backspace, monitor goes to sleep immediately. Alt+Sysrq combinations are usually working and also ssh.

System journal contains:
 kernel: nouveau 0000:01:00.0: fifo: CACHE_ERROR - ch 16 [soffice.bin[30009]] subc 5 mthd 0184 data beef0201

... and many similar lines with changing numbers after subc, mthd and data.
Folowed by:
/usr/libexec/gdm-x-session[11881]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 55765, resource id: 100663298, major code: 18 (ChangeProperty), minor code: 0

and
kernel: nouveau 0000:01:00.0: gr: TRAP_CCACHE 00000001 [FAULT]
kernel: nouveau 0000:01:00.0: gr: TRAP_CCACHE 000e0080 00000000 00000000 00000000 00000000 00000004 00000000
kernel: nouveau 0000:01:00.0: gr: 00200000 [] ch 16 [001eb0f000 soffice.bin[30009]] subc 3 class 8597 mthd 13bc data 00000054
kernel: nouveau 0000:01:00.0: fb: trapped read at 002027ff00 on channel 16 [1eb0f000 soffice.bin[30009]] engine 00 [PGRAPH] client 05 [CCACHE] subclient 00 [CB] reason 00.......
kernel: nouveau 0000:01:00.0: gr: PGRAPH TLB flush idle timeout fail
kernel: nouveau 0000:01:00.0: gr: PGRAPH_STATUS 00000503 [BUSY DISPATCH CTXPROG CCACHE_PREGEOM]
kernel: nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS0: 00000008 [CCACHE]
kernel: nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS1: 00000000 []
kernel: nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS2: 00000000 []
(EE) [mi] EQ overflowing. Additional events will be discarded until existing events are processed.
(EE)
(EE) Backtrace:
(EE) 0: /usr/libexec/Xorg (mieqEnqueue+0x253) [0x578753]
(EE) 1: /usr/libexec/Xorg (QueuePointerEvents+0x52) [0x44f352]
(EE) 2: /usr/lib64/xorg/modules/input/evdev_drv.so (_init+0x30eb) [0x7f1f83f13dfb]
(EE) 3: /usr/lib64/xorg/modules/input/evdev_drv.so (_init+0x3855) [0x7f1f83f15035]
(EE) 4: /usr/libexec/Xorg (DPMSSupported+0xe8) [0x4769c8]
(EE) 5: /usr/libexec/Xorg (xf86SerialModemClearBits+0x2b2) [0x49fe62]
(EE) 6: /lib64/libc.so.6 (__restore_rt+0x0) [0x7f1f8df6fb1f]
(EE) 7: /lib64/libc.so.6 (ioctl+0x5) [0x7f1f8e033705]
(EE) 8: /lib64/libdrm.so.2 (drmIoctl+0x28) [0x7f1f8f32f508]
(EE) 9: /lib64/libdrm.so.2 (drmCommandWrite+0x1b) [0x7f1f8f33208b]
(EE) 10: /lib64/libdrm_nouveau.so.2 (nouveau_bo_wait+0xbc) [0x7f1f88a2637c]
(EE) 11: /usr/lib64/xorg/modules/drivers/nouveau_drv.so (_init+0x75f9) [0x7f1f88c3ed19]
(EE) 12: /usr/lib64/xorg/modules/drivers/nouveau_drv.so (_init+0x801d) [0x7f1f88c400ed]
(EE) 13: /usr/libexec/Xorg (DRI2SwapBuffers+0x1c8) [0x569268]
(EE) 14: /usr/libexec/Xorg (DRI2GetParam+0xb7c) [0x56ae0c]
(EE) 15: /usr/libexec/Xorg (SendErrorToClient+0x2df) [0x4369bf]
(EE) 16: /usr/libexec/Xorg (remove_fs_handlers+0x453) [0x43a9e3]
(EE) 17: /lib64/libc.so.6 (__libc_start_main+0xf0) [0x7f1f8df5b580]
(EE) 18: /usr/libexec/Xorg (_start+0x29) [0x424ce9]
(EE) 19: ? (?+0x29) [0x29]
(EE)
(EE) [mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.
(EE) [mi] mieq is *NOT* the cause. It is a victim.
(EE) [mi] EQ overflow continuing. 100 events have been dropped.
(EE)