Bug 18331

Summary:	kernel warning "vblank wait timed out on crtc 0" at boot and when switching Vt's
Product:	Mageia	Reporter:	alain bonis <albonis>
Component:	RPM Packages	Assignee:	Kernel and Drivers maintainers <kernel>
Status:	NEW ---	QA Contact:
Severity:	normal
Priority:	Normal	CC:	ennael1, marja11, pterjan
Version:	Cauldron
Target Milestone:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Source RPM:	kernel-4.6.0-0.rc5.2.mga6.src.rpm	CVE:
Status comment:
Attachments:	journal trace lspci

Description alain bonis 2016-05-02 22:16:16 CEST

Description of problem:
the journal show kernel warnings (see atachement) about drm :

mai 02 21:50:56 zephir kernel: WARNING: CPU: 1 PID: 1071 at drivers/gpu/drm/drm_irq.c:1326 drm_wait_one_vblank+0x198/0x1a0 [drm]
mai 02 21:50:56 zephir kernel: vblank wait timed out on crtc 0

these warnings appear at boot, and when switching from gui to vt's and back.
Other than the warnings, i did not notice any malfunction. But nevertheless, it's ugly.

A bug for the same problem has been files at freedesktop :
https://bugs.freedesktop.org/show_bug.cgi?id=93782

Version-Release number of selected component (if applicable):

kernel-4.6.0-0.rc5.2.mga6

How reproducible:
every boot, and  each switch from gui to vt's and back

Steps to Reproduce:
1.from gui : CTRL+F2 to go to vt2, then CTRL+F1 to go back to gui
2.
3.

Comment 1 alain bonis 2016-05-02 22:18:27 CEST

Created attachment 7733 [details]
journal trace

Comment 2 alain bonis 2016-05-02 22:19:20 CEST

Created attachment 7734 [details]
lspci

Marja Van Waes 2016-05-02 22:35:18 CEST

CC: (none) => marja11
Assignee: bugsquad => tmb

Comment 3 Marja Van Waes 2016-08-26 11:43:21 CEST

Mass-reassigning all bugs with "kernel" in the Source RPM field that are assigned to tmb, to the kernel packagers group, because tmb is currently MIA.

Assignee: tmb => kernel

Comment 4 Anne Nicolas 2016-11-06 20:58:53 CET

Same problem here now, quite annoying as I cannot use mouse unless switching to console and back to graphical interface. After having a look I found that bug about Intel graphics:

https://bugs.freedesktop.org/show_bug.cgi?id=93782
For now it seems there is no fix available :/

CC: (none) => ennael1

Comment 5 Pascal Terjan 2016-11-07 11:22:11 CET

Reading the stacktrace, I guess xorg is asking the kernel to detect if there is a TV connected on the TV out connector and what it would support.

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree//drivers/gpu/drm/i915/intel_tv.c#n1329

Still, it is only waiting for 100ms so shouldn't be really noticeable except for the log spam


Possibly related code I noticed:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree//drivers/gpu/drm/i915/intel_tv.c#n848

CC: (none) => pterjan