Bug 92175 - [HSW]Unable to connect 4K display FIFO underrun on pipe C.
Summary: [HSW]Unable to connect 4K display FIFO underrun on pipe C.
Status: CLOSED FIXED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-09-29 05:50 UTC by acez
Modified: 2016-10-18 13:04 UTC (History)
1 user (show)

See Also:
i915 platform: HSW
i915 features: display/DP


Attachments
dmesg output with kernel stack trace (11.05 KB, text/plain)
2015-09-29 05:56 UTC, acez
no flags Details

Description acez 2015-09-29 05:50:26 UTC
Hi,
 I am using a Lenovo Thinkpad t540p running ArchLinux (so most likely running latest version of intel driver). I have a docking station and am trying to connect a Dell P2415Q monitor to it through DP. Using xrandr or arandr, I can see that the monitor is successfully detected but when I enable it, although it says that the monitor is enabled, I don't see any output on the screen and I get the following in dmesg:
[drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe C
[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe C FIFO underrun
When I enable MST on the monitor however, it seems to work. But using MST this monitor cannot run at 60hz.
Any clues on what the issue could be ?
Comment 1 acez 2015-09-29 05:56:03 UTC
Created attachment 118511 [details]
dmesg output with kernel stack trace

Also, when I turn the monitor off and then back on I get the following in dmesg.
Comment 2 Jani Nikula 2015-10-30 13:25:16 UTC
Please try Ville's FIFO underrun elimination series [1] on top of drm-intel-nightly, also available at [2], and report back.

[1] http://mid.gmane.org/1446146763-31821-1-git-send-email-ville.syrjala@linux.intel.com
[2] git://github.com/vsyrjala/linux.git pch_fifo_underrun_fix_4
Comment 3 Dhinakaran Pandiyan 2016-07-07 06:13:38 UTC
Please re-open the bug if the issue still exists on the latest drm-intel-nightly. I am closing this as there has been no response for some time now.


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