Bug 95467

Summary: GPU hangs in v4.6 on CHT
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: normal    
Priority: medium CC: intel-gfx-bugs
Version: XOrg git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: BSW/CHT i915 features: GPU hang
Attachments:
Description Flags
dmesg log for first test
none
log from /sys/class/drm/card0/error
none
dmesg for second test
none
error for second test none

Description Pierre Bossart 2016-05-18 00:03:38 UTC
Created attachment 123857 [details]
dmesg log for first test

V4.5 works fine on CHT (Tronsmart Ara X5 Plus)
V4.6 is broken, UI is frozen in less than 20 seconds when moving windows around.

the drm-intel-nightly works fine, apparently due to this commit:

commit a5e485a95c9c4cdd93b4c6dc53eee3bd1e50de11
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Wed Apr 13 21:19:51 2016 +0300

    drm/i915: Clear VLV_IER around irq processing


Attached results of 2 tests which show similar behavior.
Comment 1 Pierre Bossart 2016-05-18 00:04:42 UTC
Created attachment 123858 [details]
log from /sys/class/drm/card0/error
Comment 2 Pierre Bossart 2016-05-18 00:05:08 UTC
Created attachment 123859 [details]
dmesg for second test
Comment 3 Pierre Bossart 2016-05-18 00:05:33 UTC
Created attachment 123860 [details]
error for second test
Comment 4 Pierre Bossart 2016-05-18 20:21:14 UTC
The commit 9dbaab56ac09 ("drm/i915: Exit cherryview_irq_handler() after one pass"
seems to be the root cause.

git revert 9dbaab56ac09 works fine on top of v4.6 on my Tronsmart Ara X5 Plus
Comment 5 Chris Wilson 2017-02-04 20:43:13 UTC
commit dd218276595f35a9a3e2fe1d0f1ed34634cac623
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Wed Jun 22 15:23:03 2016 -0700

    Revert "drm/i915: Exit cherryview_irq_handler() after one pass"
    
    This reverts commit 9dbaab56ac09f07a73fe83bf69bec3e31060080a.
    
    Turns out it was a bad idea and was fixed up "properly" in 4.7 but those
    patches are too big to put into 4.6, so let's just revert it for now.
    
    Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
    Cc: Daniel Vetter <daniel@ffwll.ch>
    Cc: Peter Frühberger <peter.fruehberger@gmail.com>
    Cc: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Jani Nikula <jani.nikula@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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