Bug 93787 - [BAT ILK] sporadic fifo underruns in igt@kms_flip@basic-flip-vs-* on ilk-hp8440p
Summary: [BAT ILK] sporadic fifo underruns in igt@kms_flip@basic-flip-vs-* on ilk-hp8440p
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: XOrg git
Hardware: Other All
: highest critical
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Depends on:
Reported: 2016-01-20 09:06 UTC by Daniel Vetter
Modified: 2017-07-24 22:43 UTC (History)
2 users (show)

See Also:
i915 platform: ILK
i915 features: display/atomic


Description Daniel Vetter 2016-01-20 09:06:22 UTC
Noticed while reviewing Matt's atomic wm revert patch that we have fifo underruns pre-existing on this platform. Somehow only happens on this testcase. For context the long-term view:

Comment 1 Ville Syrjala 2016-01-20 11:02:59 UTC
I suppose I missed some other ilk/ibx corner case when trying to fix it all. Sigh.
Comment 2 Mika Kuoppala 2016-01-20 15:35:49 UTC
Got it on basic-flip-vs-modeset also
Comment 3 Dave Gordon 2016-01-20 17:19:45 UTC
Also shows intermittently in hang-read-crc-pipe-a and read-crc-pipe-b.

c.f. also https://bugs.freedesktop.org/show_bug.cgi?id=93640
Comment 4 Dave Gordon 2016-01-22 15:05:57 UTC
Also seen in read-crc-pipe-a-frame-sequence.

In fact I think it can happen in pretty much any of the kms_* tests.
Comment 6 Ville Syrjala 2016-04-12 17:55:59 UTC
Hopefully fixed now

commit 1204d5baa8781a1bf968244bd2b0f15ed861e573
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Fri Apr 1 21:53:18 2016 +0300

    drm/i915: Make sure LP1+ watermarks levels are preserved when going from 1 to 2 pipes

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