Also seen on HSW peppy (chromebook): 

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_30/fi-hsw-peppy/igt@kms_plane_lowres@pipe-c-tiling-x.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_30/fi-hsw-peppy/igt@kms_plane_lowres@pipe-c-tiling-none.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_94/fi-byt-clapper/igt@kms_plane_lowres@pipe-b-tiling-none.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_94/fi-byt-clapper/igt@kms_plane_lowres@pipe-a-tiling-x.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_94/fi-byt-clapper/igt@kms_plane_lowres@pipe-b-tiling-x.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_94/fi-byt-clapper/igt@kms_plane_lowres@pipe-a-tiling-none.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_95/fi-byt-clapper/igt@kms_plane_lowres@pipe-a-tiling-x.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_95/fi-byt-clapper/igt@kms_plane_lowres@pipe-a-tiling-none.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_95/fi-byt-clapper/igt@kms_plane_lowres@pipe-b-tiling-x.html

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_95/fi-byt-clapper/igt@kms_plane_lowres@pipe-b-tiling-none.html

(kms_plane_lowres:1276) igt_kms-CRITICAL: Test assertion failure function igt_assert_plane_visible, file ../lib/igt_kms.c:1684:
(kms_plane_lowres:1276) igt_kms-CRITICAL: Failed assertion: visible == visibility
(kms_plane_lowres:1276) igt_kms-CRITICAL: Last errno: 9, Bad file descriptor
(kms_plane_lowres:1276) igt_kms-CRITICAL: error: 1 != 0

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_110/fi-snb-2520m/igt@kms_plane_lowres@pipe-a-tiling-x.html

Starting subtest: pipe-A-tiling-x
(kms_plane_lowres:1130) igt_kms-CRITICAL: Test assertion failure function igt_assert_plane_visible, file ../lib/igt_kms.c:1626:
(kms_plane_lowres:1130) igt_kms-CRITICAL: Failed assertion: visible == visibility
(kms_plane_lowres:1130) igt_kms-CRITICAL: Last errno: 9, Bad file descriptor
(kms_plane_lowres:1130) igt_kms-CRITICAL: error: 1 != 0
Subtest pipe-A-tiling-x failed.

<3> [79.466838] [drm:drm_crtc_add_crc_entry] *ERROR* Overflow of CRC buffer, userspace reads too slow.

This test puts a canary plane in the bottom left corner of the screen, then switches to a smaller mode in which the plane is now fully offscreen; if the driver still reports the plane as on-screen after the modeset then the test fails.

I believe the failures here arise from test's fallback logic when it can't find a suitable mode on the connector's modelist (e.g., because it's something like an eDP panel that only has a single mode listed) --- the test uses a fixed 1024x768 mode in that case.  However the test doesn't actually check to ensure 1024x768 is truly small enough to ensure the plane is offscreen.  If the panel was originally running with something like 1366x768 (which some of our CI machines are), then a plane in the bottom left corner will still be visible after switching to 1024x768.

I'm testing out a possible fix on trybot; will update tomorrow if it actually solves the problem here.

Proposed fix was submitted here:

https://patchwork.freedesktop.org/series/65485/#rev1

Back in the day, when the test was written, there were no real reason why 1024x768 resolution was selected. It was readily available in igt_kms.c as a function and the same resolution were used in other tests as well. 

We could easily use smaller 640x480 resolution, which should be small enough that most of the problematic platforms would be tested instead of skipping. However, this doesn't change the fact that we should test if the resolution is small enough to ensure the plane will be offscreen.

Fix merged.

reproduction rate was 100% 2 months 2 weeks ago(drmtip 354), not seen in the last 46 runs, so archiving this

The CI Bug Log issue associated to this bug has been archived.

New failures matching the above filters will not be associated to this bug anymore.