Bug 98990

Summary: [SKL] Oops when turning second external DP monitor off
Product: DRI Reporter: Pierre Bossart <pierre-louis.bossart>
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: major    
Priority: medium CC: intel-gfx-bugs, nathan.d.ciobanu
Version: XOrg git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
i915 platform: BXT, KBL, SKL i915 features: display/DP MST
Description Flags
kernel oops on fedora 24 v4.8.8
dmesg w/ drm-intel-nightly from 12/2 with drm.debug=0x1e
Suggested patch removes oops
patch v2 based on Chris Wilson's suggestion none

Description Pierre Bossart 2016-12-04 20:48:36 UTC
Created attachment 128335 [details]
kernel oops on fedora 24 v4.8.8

On SKL SkullCanyon NUC, turning off or changing input of second DP external monitor results in a kernel Oops reproducible 100% of the time.

initial dmesg output captured over ssh attached, will run with latest drm/drm-intel-nightly later and add more information.
Comment 1 Pierre Bossart 2016-12-04 23:43:25 UTC
Bug confirmed with drm-intel-nightly w/ Friday 12/2 code, see dmesg with drm.debug=0x1e attached.
Comment 2 Pierre Bossart 2016-12-04 23:44:33 UTC
Created attachment 128336 [details]
dmesg w/ drm-intel-nightly from 12/2 with drm.debug=0x1e
Comment 3 Pierre Bossart 2016-12-05 01:22:20 UTC
Created attachment 128339 [details] [review]
Suggested patch removes oops
Comment 4 yann 2016-12-05 07:06:46 UTC
Reference to Pierre's patch: https://patchwork.freedesktop.org/series/16337/
Comment 5 Pierre Bossart 2016-12-05 21:50:54 UTC
Created attachment 128349 [details] [review]
patch v2 based on Chris Wilson's suggestion
Comment 6 nathan.d.ciobanu 2017-01-25 23:30:28 UTC
I tested the patch and it fixed the bug.
Comment 7 Radhakrishna Sripada 2017-02-13 22:42:19 UTC
Thr patch mentioned in comment 5 fixes a skylake regression in ChromeOS. 
Can this patch be reviewed and merged?
Comment 8 Jani Nikula 2017-02-15 09:54:04 UTC

commit bb08c04dc867b5f392caec635c097d5d5fcd8c9f
Author: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date:   Tue Feb 14 14:49:21 2017 +0200

    drm/dp/mst: fix kernel oops when turning off secondary monitor

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