Bug 105604 - [CI][KBL only] igt@* - dmesg-warn - *ERROR* CPU pipe [A|B] FIFO underrun
Summary: [CI][KBL only] igt@* - dmesg-warn - *ERROR* CPU pipe [A|B] FIFO underrun
Status: NEW
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: DRI git
Hardware: Other All
: high normal
Assignee: Mun, Gwan-gyeong
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard: ReadyForDev
Keywords:
Depends on:
Blocks: 105980
  Show dependency treegraph
 
Reported: 2018-03-19 14:26 UTC by Marta Löfstedt
Modified: 2019-01-30 16:42 UTC (History)
2 users (show)

See Also:
i915 platform: KBL
i915 features: display/Other


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Description Marta Löfstedt 2018-03-19 14:26:13 UTC
This bug is intended for KBL FIFO underruns.

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_4/fi-kbl-7500u/igt@kms_cursor_legacy@cursora-vs-flipa-toggle.html

[   43.184721] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[   43.185236] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
Comment 1 Marta Löfstedt 2018-03-21 09:45:23 UTC
https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_5/fi-kbl-7500u/igt@gem_mmap_gtt@basic-wc.html

[   43.013962] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
Comment 2 Marta Löfstedt 2018-03-23 10:40:25 UTC
https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_6/fi-kbl-7500u/igt@kms_cursor_legacy@cursorb-vs-flipb-toggle.html

[  135.131495] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
Comment 3 Marta Löfstedt 2018-04-03 12:35:16 UTC
https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_9/fi-kbl-7500u/igt@perf_pmu@semaphore-wait-bcs0.html
	

[  190.129475] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
Comment 5 Marta Löfstedt 2018-04-06 08:20:51 UTC
(In reply to Marta Löfstedt from comment #4)
> https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_12/fi-skl-6770hq/
> igt@gem_exec_schedule@reorder-wide-bsd2.html

Wrong bug
Comment 7 Francesco Balestrieri 2018-06-01 07:49:20 UTC
Still seen
Comment 8 Mun, Gwan-gyeong 2019-01-25 06:58:38 UTC
After investigating the issue, I am suspecting a GEN9 hardware issue.
I figured out enabling FBC on a plane which has a combination of a 180-degree rotation with having a Height that isn't divisible by 4 occasionally causes FIFO underrun.
I tested the issue with igt-gpu-tools. ( multiplane-rotation-cropping-top subtest from kms_rotation_crc).
I tested on Gen9 disaply HWs (both Skylake and Kabylake).
when I added the patch code which make avoiding the issue case, I could always passed the test case.
https://gitlab.freedesktop.org/elongbug/drm-tip/tree/gen9_fbc_underrun01
https://gitlab.freedesktop.org/elongbug/drm-tip/commit/a3969a959230153a53088a0abbf354c4c233af20

I asked a HW guy this issue to clarify.
And for now I am waiting the reply.
Comment 9 Mun, Gwan-gyeong 2019-01-29 12:25:54 UTC
I received a guide of the issue from HW Team .
He guided me that we should disable FBC when 180 rotation and non-divisible by 4 plane size scenarios on GEN9

Issue case:
 Enabling FBC on a plane which has a combination of a 180-degree rotation with having a Height that isn't divisible by 4  occasionally causes FIFO underrun.

Solution: 
 Disabling FBC on a plane which has a combination of a 180-degree rotation with having a Height that isn't divisible by 4 to GEN9
Comment 10 Mun, Gwan-gyeong 2019-01-29 12:58:39 UTC
https://patchwork.freedesktop.org/patch/281708/
Comment 11 Jose Roberto de Souza 2019-01-30 16:42:32 UTC
Hi Gwan-gyeong

HW will add or already have added this information to BSpec?


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