Bug 28331 - screen flickers all the time with desktop image appearing only briefly
Summary: screen flickers all the time with desktop image appearing only briefly
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Radeon (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium critical
Assignee: Default DRI bug account
QA Contact:
Depends on:
Reported: 2010-05-31 08:45 UTC by Gildas Le Nadan
Modified: 2010-06-08 16:45 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

Xorg.0.log (32.10 KB, patch)
2010-05-31 08:45 UTC, Gildas Le Nadan
no flags Details | Splinter Review
dmesg (43.93 KB, text/plain)
2010-05-31 08:46 UTC, Gildas Le Nadan
no flags Details
avivotool dumps with kms (v2.6.34) (294 bytes, text/plain)
2010-06-02 03:30 UTC, Gildas Le Nadan
no flags Details
avivotool dumps with ums (v2.6.34 radeon.modeset=0) (293 bytes, text/plain)
2010-06-02 03:34 UTC, Gildas Le Nadan
no flags Details
possible fix (1.07 KB, patch)
2010-06-08 14:44 UTC, Alex Deucher
no flags Details | Splinter Review

Description Gildas Le Nadan 2010-05-31 08:45:53 UTC
Created attachment 35972 [details] [review]

Machine is an Acer Aspire L5100 with an AMD Athlon 64 X2 Dual Core Processor 4000+ running a 64 bits debian sid.

The machine is a small factor desktop machine designed around laptop components, so the graphic card is an integrated radeon x1200.

When running a linux vanilla kernel 2.6.34, the screen flickers all the time making the machine unusable, while with kernel 2.6.33 such "flick to black" event occured from time to time but most of the time the desktop was correctly displayed.

radeon.new_pll=0 doesn't solve the problem
radeon.nomodeset=0 does

The problem was bisected to commit 383be5d1789d9a7a2e77dca1cb0aca89507d069e

The following packages version are installed:
xserver-xorg                           1:7.5+6
xserver-xorg-core                      2:1.7.7-1
xserver-xorg-video-radeon              1:6.13.0-2

Please find attached Xorg.0.log and dmesg for that machine (when booted on 2.6.34 with no radeon option).
Comment 1 Gildas Le Nadan 2010-05-31 08:46:24 UTC
Created attachment 35973 [details]
Comment 2 Alex Deucher 2010-06-01 22:14:15 UTC
Can you dump the following regs using avivotool in both kms and ums?  You can get avivotool here:
and most distros package it.
avivotool regmatch 0x0400 >> kms.out
avivotool regmatch 0x0404 >> kms.out
avivotool regmatch 0x0430 >> kms.out
avivotool regmatch 0x0438 >> kms.out
avivotool regmatch 0x043c >> kms.out
avivotool regmatch 0x0450 >> kms.out
avivotool regmatch 0x0410 >> kms.out
avivotool regmatch 0x0414 >> kms.out
avivotool regmatch 0x0434 >> kms.out
avivotool regmatch 0x0440 >> kms.out
avivotool regmatch 0x0444 >> kms.out
avivotool regmatch 0x0454 >> kms.out
Comment 3 Gildas Le Nadan 2010-06-02 03:30:59 UTC
Created attachment 36005 [details]
avivotool dumps with kms (v2.6.34)
Comment 4 Gildas Le Nadan 2010-06-02 03:34:28 UTC
Created attachment 36006 [details]
avivotool dumps with ums (v2.6.34 radeon.modeset=0)
Comment 5 Alex Deucher 2010-06-08 14:44:01 UTC
Created attachment 36167 [details] [review]
possible fix

Does this drm kernel patch help?
Comment 6 Gildas Le Nadan 2010-06-08 16:36:50 UTC
Thanks Alex: I applied the patch on top of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git and it seems to fix the "flicker all the time issue" for me.
Comment 7 Alex Deucher 2010-06-08 16:45:15 UTC
I've sent it to Dave for inclusion in the kernel.

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