Bug 43348 - [ILK dp] blank screen at boot after kms
Summary: [ILK dp] blank screen at boot after kms
Status: RESOLVED OBSOLETE
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(DRI - Intel) (show other bugs)
Hardware: All Linux
: P1 high
Assignee: drivers_video-dri-intel@kernel-bugs.osdl.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-06-07 11:12 UTC by Matthieu Imbert
Modified: 2012-06-28 09:10 UTC (History)
2 users (show)

See Also:
Kernel Version: 3.2.0
Subsystem:
Regression: No
Bisected commit-id:

Attachments
full dmesg of failed KMS during boot with drm.debug=0xe (122.93 KB, text/plain)
2012-06-08 06:22 UTC, Matthieu Imbert 		Details
full dmesg of successful KMS during boot with drm.debug=0xe (121.57 KB, text/plain)
2012-06-08 06:22 UTC, Matthieu Imbert 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Matthieu Imbert 2012-06-07 11:12:45 UTC 
Hardware: Dell E4310 laptop with integrated Intel HD Graphics Chipset

When i boot, more than 50% of the time, KMS fails for the laptop screen, with message:
[drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting

Then, the screen is either black or contains some garbage. I'm able to get other the issue by putting the laptop in software suspend and immediately resume it, then i get back a correct screen.

If needed, i can compile a kernel with patches or another kernel version to check.
Comment 1 Chris Wilson 2012-06-07 11:14:59 UTC 
3.2 is notorious for its DP regressions, can you please retest with say 3.4?
Comment 2 Daniel Vetter 2012-06-07 12:01:07 UTC 
Also, please attach full dmesg with drm.debug=0xe added to your kernel cmdline.
Comment 3 Matthieu Imbert 2012-06-08 06:20:29 UTC 
Ok, i will test with 3.4.

In the meantime, i attach two full dmesg with drm.debug=0xe. One dmesg is for a successful KMS during boot, the other is for a failed KMS during boot.

Since I added drm.debug=0xe, the frequency of KMS failure at boot time is noticeably lower. It was more than 50% before (perhaps 60% to 70%), it is now something like 10%
Comment 4 Matthieu Imbert 2012-06-08 06:22:18 UTC 
Created attachment 73540 [details]
full dmesg of failed KMS during boot with drm.debug=0xe
Comment 5 Matthieu Imbert 2012-06-08 06:22:40 UTC 
Created attachment 73541 [details]
full dmesg of successful KMS during boot with drm.debug=0xe
Comment 6 Matthieu Imbert 2012-06-28 09:10:51 UTC 
This bug is fixed with 3.2.20 (tested with the latest debian kernel linux-image-3.2.0-2-rt-amd64 version 3.2.20-1)
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