Bug 82801 - broken DP on 3.16
Summary: broken DP on 3.16
Status: RESOLVED CODE_FIX
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(DRI - Intel) (show other bugs)
Hardware: All Linux
: P3 normal
Assignee: Jani Nikula
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-08-19 20:24 UTC by Rob Clark
Modified: 2014-09-23 14:08 UTC (History)
1 user (show)

See Also:
Kernel Version: 3.16
Subsystem:
Regression: No
Bisected commit-id:

Attachments
dmesg w/ drm.debug=15 (736.45 KB, text/plain)
2014-08-19 20:24 UTC, Rob Clark 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Rob Clark 2014-08-19 20:24:05 UTC 
Created attachment 147351 [details]
dmesg w/ drm.debug=15

observed on thinkpad t500.  Fails to light up external DP, with the following warning:

   mismatch in limited_color_range (expected 1, found 0)

dmesg attached
Comment 1 Rob Clark 2014-08-19 20:55:45 UTC 
ok, small correction..  was having some monitor issues.  DP *does* light up (but still with the attached WARN_ON() splat)
Comment 2 Jani Nikula 2014-08-20 07:31:43 UTC 
(In reply to Rob Clark from comment #0)
> Created attachment 147351 [details]
> dmesg w/ drm.debug=15

Rob, although DRM_DEBUG is there, I'm not seeing any DRM_DEBUG_KMS or DRM_DEBUG_DRIVER output. Please check your debug parameter. Also I'm not too interested in the core stuff, so drm.debug=14 should be sufficient.
Comment 3 Rob Clark 2014-08-20 11:44:31 UTC 
(In reply to Jani Nikula from comment #2)
> (In reply to Rob Clark from comment #0)
> > Created attachment 147351 [details]
> > dmesg w/ drm.debug=15
> 
> Rob, although DRM_DEBUG is there, I'm not seeing any DRM_DEBUG_KMS or
> DRM_DEBUG_DRIVER output. Please check your debug parameter. Also I'm not too
> interested in the core stuff, so drm.debug=14 should be sufficient.

The intel_dump_pipe_config() traces are all DRM_DEBUG_KMS().. fwiw, these traces are from 'dmesg' (rather than console or anything that should be filtered by loglevel).  I don't have access to that setup today, so if you need anything more, or want me to try something, I'll have to do that tomorrow.
Comment 4 Jani Nikula 2014-09-23 14:08:00 UTC 
Presumed fixed by

commit 8c875fca1a8d76665c60fa141c220cee65f44f5e
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Fri Sep 12 15:46:29 2014 +0300

    drm/i915: Add limited color range readout for HDMI/DP ports on g4x/vlv/chv

in v3.17-rc6. Please reopen if the problem persists.
Note You need to log in before you can comment on or make changes to this bug.