Bug 56401

Summary: [IVB eDP stable-regression] laptop screen does not come up until a suspend/resume cycle happens.
Product: DRI Reporter: roberth <sarvatt>
Component: DRM/IntelAssignee: Daniel Vetter <daniel>
Status: CLOSED FIXED QA Contact:
Severity: normal    
Priority: high CC: ben, chris, daniel, jani.nikula, jbarnes
Version: XOrg git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
i915 platform: i915 features:
Description Flags
dmesg after reproducing it with drm.debug=0xe
intel_reg_dumper output (working)
intel_reg_dumper output (failing)
3.6.3 dmesg
edid none

Description roberth 2012-10-25 16:24:06 UTC
Created attachment 69076 [details]
dmesg after reproducing it with drm.debug=0xe

This commit causes a lenovo v490u to have a black screen after booting


It's working properly in 3.7, but 3.6 is broken without reverting that, and that commit was backported to the stable kernels which are now broken also. Suspending/resuming the machine after booting brings the display back up.

(working with revert)
[   12.179335] [drm:intel_choose_pipe_bpp_dither], clamping display bpc (was -1) to eDP (6)
[   12.179337] [drm:intel_choose_pipe_bpp_dither], setting pipe bpc to 8 (max display bpc 6)

[   14.264823] [drm:intel_choose_pipe_bpp_dither], setting pipe bpc to 8 (max display bpc 8)
Comment 1 roberth 2012-10-25 16:24:52 UTC
Created attachment 69077 [details]
intel_reg_dumper output (working)
Comment 2 roberth 2012-10-25 16:25:16 UTC
Created attachment 69078 [details]
intel_reg_dumper output (failing)
Comment 3 Daniel Vetter 2012-10-25 18:52:31 UTC
Please double-check whether your 3.6 tree contains:

commit 0c96c65b48fba3ffe9822a554cbc0cd610765cd5
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Wed Sep 26 18:43:10 2012 +0300

    drm/i915: use adjusted_mode instead of mode for checking the 6bpc force flag

This should fix fallout from the cited commit.
Comment 4 roberth 2012-10-25 19:24:19 UTC
No luck unfortunately, tried 3.2.32 and 3.6.3 that both contain that commit and they have the same problem.
Comment 5 roberth 2012-10-25 19:24:49 UTC
Created attachment 69090 [details]
3.6.3 dmesg
Comment 6 Jani Nikula 2012-11-07 11:20:13 UTC
Related to https://bugzilla.kernel.org/show_bug.cgi?id=47641

Robert, please add the hex dump of your EDID from /sys/class/drm/*/edid, where * is your display.
Comment 7 roberth 2012-11-09 15:19:20 UTC
Created attachment 69821 [details]

Comment 8 roberth 2012-11-11 15:56:01 UTC
Another eDP machine (dell e6510) broken by this commit on 

Comment 9 Daniel Vetter 2012-11-13 12:15:59 UTC
Revert merged to -fixes:

commit 2f4f649a69a9eb51f6e98130e19dd90a260a4145
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Mon Nov 12 14:33:44 2012 +0200

    drm/i915: do not ignore eDP bpc settings from vbt

Please yell if this is still an issue for you.

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