Bug 107400

Summary: [CI][BAT] igt@drv_selftest@live_coherency - dmesg-fail - Value[0/7] mismatch, (overwrite with cpu) wrote [gtt] a3b52fe8 read [cpu] 5c4ad017 (inverse 5c4ad017), at offset 5dc
Product: DRI Reporter: Martin Peres <martin.peres>
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: ReadyForDev
i915 platform: ICL i915 features: GEM/Other

Description Martin Peres 2018-07-27 11:19:24 UTC 
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_4554/fi-icl-u/igt@drv_selftest@live_coherency.html

[  605.873903] Value[0/7] mismatch, (overwrite with cpu) wrote [gtt] a3b52fe8 read [cpu] 5c4ad017 (inverse 5c4ad017), at offset 5dc
[  605.873953] i915/i915_gem_coherency_live_selftests: igt_gem_coherency failed with error -22
[  605.975469] i915: probe of 0000:00:02.0 failed with error -22
Comment 1 Chris Wilson 2018-08-01 13:18:33 UTC 
commit 21eb1850fa0bd0a9b729bf3708da78888433027f (HEAD -> drm-intel-next-queued, drm-intel/for-linux-next, drm-intel/drm-intel-next-queued)
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Aug 1 11:47:21 2018 +0100

    drm/i95: Mark GGTT as incoherent for gen10+
    
    The evidence suggests that we need to start treating writes via GGTT as
    incoherent for gen10+, that is that they are internally buffered and not
    immediately visible via a read along a different physical path.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107398
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107400
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107435
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
    Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20180801104721.4030-1-chris@chris-wilson.co.uk

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