Bug 91745

Summary: Xorg intel driver makes console unsynced
Product: DRI Reporter: Samuel Thibault <samuel.thibault>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium CC: intel-gfx-bugs
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:

Description Samuel Thibault 2015-08-24 16:30:27 UTC
Hello,

I have installed a brand new HP EliteBook 820 G2 with Debian Stretch, which includes the Xorg server version 1.17.2 and the Intel driver 2.99.917.

At boot, the Linux console is fine. Then I start Xorg, and when I get back to the console (either through quitting Xorg or ctrl-alt-f2), the console output comes back, but the horizontal synchronization seems to be nonfunctional: the output keeps scrolling horizontally. I can type text, run commands, etc. so it's really just the output which is buggy.

One very odd thing is that if I consume CPU (e.g. through while true ; do : ; done), the display becomes perfectly stable and the console is usable again. This doesn't depend on the CPU which I run that on. I guess this may be related with CPU sleep modes.

Downgrading the Xorg server to 1.16.4 and the intel driver to 2.21.15 fixes the issue, I'll probably try to bisect a bit (at least try to use the same Xorg server)

This is basically making my laptop unusable for my work without a downgrade :)
Comment 1 Chris Wilson 2015-08-24 16:39:44 UTC
'Tis a kernel bug, update your kernel or use i915.enable_ips in the meantime.
Comment 2 Samuel Thibault 2015-08-24 17:46:37 UTC
Indeed, enable_ips=0 or upgrading to linux 4.2 rc8 instead of just 4.1.3 fixes the issue
Comment 3 Elizabeth 2017-10-06 14:29:35 UTC
Closing old verified.

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