Bug 93393

Summary: Regression for Skylake modesetting in kernel 4.4 with 2 Displays of different resolution
Product: DRI Reporter: Kai Iskratsch <kai>
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: critical    
Priority: highest CC: intel-gfx-bugs
Version: unspecifiedKeywords: regression
Hardware: Other   
OS: Linux (All)   
Whiteboard:
i915 platform: SKL i915 features: display/DP MST
Attachments:
Description Flags
Kernel Log of failed kms on one display (drm.debug=0x0e) none

Description Kai Iskratsch 2015-12-16 07:27:52 UTC 
Created attachment 120534 [details]
Kernel Log of failed kms on one display (drm.debug=0x0e)

i am testing kernel 4.4 RC cause of the problems in Bug 89055.  while it looked very good yesterday today on freshly turning on the computer i noticed a big regression.
I have 2 displays with different resolution one Full HD display connected via HDMI, and one 1680x1050 which is connected via DVI. 
And with kernel 4.4 on a freshly tuned on system the 1680x1050 Display turns off itself with an out of range error. i tried it a few times, and it was completely reproducable as long as the system was freshly turned on, when i boot once with kernel 4.3 and then reboot with 4.4 then everyting works.

on the last bug someone told me to enable drm.debug=0x0e so i attach a log with that option turned on, hope it helps.
Comment 1 Kai Iskratsch 2015-12-23 07:32:26 UTC 
any updates on this? it is still happening with the newest kernel from opensuse kernel-next repo, and will be a major problem on 4.4 release.
Comment 2 Jani Nikula 2016-04-25 09:39:57 UTC 
We seem to have completely neglected this bug. Apologies.

Does the problem persist with latest kernels and userspace?
Comment 3 Jari Tahvanainen 2017-01-31 10:57:20 UTC 
(In reply to Jani Nikula from comment #2)
> We seem to have completely neglected this bug. Apologies.
> 
> Does the problem persist with latest kernels and userspace?

Timeout, assuming that this is fixed by now. If this is not the case, please re-test with latest kernel to see if this issue is still occurring since there were improvements pushed in kernel that will benefit to your system.

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