Bug 27430

Summary: distorted display with Dell U2711 monitor with xserver-xorg-video-ati
Product: xorg Reporter: Kjell Myksvoll <kmyksvo>
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: minor    
Priority: medium    
Version: 7.5 (2009.10)   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
lspci -vvnn output
none
Xorg.0.log
none
xdpyinfo output
none
vbios dump none

Description Kjell Myksvoll 2010-04-02 11:42:02 UTC 
Created attachment 34624 [details]
lspci -vvnn output

Gets distorted display with a Dell U2711 using the KMS enabled xorg server that comes with Ubuntu Lucid (10.04).

The distortion is such that fonts are rendered almost unreadable (beside that the outline is distorted, they have a heavy red tint to them). It seems like that everything gets "overlayed" with a kind of "sawtooth" like pattern which distort everyhing, including fonts, borders on windows and edges in images and such.

The distortion is not present in screenshots.

The distortion seems to be there "all the way" from boot and up. That is the "ubuntu logo" with "progress bar" displayed during boot also displays the same distortion.

When using a different monitor, that is a Dell 2005FPW monitor, the distortion is all gone. (The U2711 uses dual channel DVI - 2560x1440 resolution, while the 2005FPW monitor uses single channel - 1680x1050 resoultion.)

The ATI fglrx driver (ver. 2:8.721-0ubuntu7) works fine with the U2711 monitor (but calculates the DPI wrong - gets 96 while it should be 109 for this monitor).

The videocard is a Radeon HD 4550 card (RV710 chip).

Have tested with the xserver-xorg-video-ati driver that comes with Ubuntu Lucid, the driver from ppa:xorg-edgers/ppa (ver. 1:6.12.192+git20100401.6baa96c4-0ubuntu0sarvatt) and with "bleeding edge" (buildt according to instructions given at http://www.x.org/wiki/radeonBuildHowTo).

From the general discussion around such issues and the KernelModeSettings found on the net, I have gotten the understanding that parts of the Xorg driver code now resides in the kernel and it could therefore be that the problem resides there and not in the xserver-xorg-video-ati/radeon driver. Have used the standard kernel (currently 2.6.32-19) that comes with Ubuntu Lucid all the way, as I have not found out how to update the KMS parts in the kernel with newer versions (pointers are most welcome). Tried with a 2.6.33 kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.33/, but this kernel gave no change (is from february and the KMS part might therefore not be up to date).
Comment 1 Kjell Myksvoll 2010-04-02 11:43:18 UTC 
Created attachment 34625 [details]
Xorg.0.log
Comment 2 Kjell Myksvoll 2010-04-02 11:43:50 UTC 
Created attachment 34626 [details]
xdpyinfo output
Comment 3 Kjell Myksvoll 2010-04-02 11:46:41 UTC 
Created attachment 34627 [details]
vbios dump

Dump taken as follows (don't know if it is of any interest though):

# cd /sys/bus/pci/devices/0000:01:00.0
# echo 1 > rom
# cat rom > /tmp/u2711.vbios
# echo 0 > rom

Ref.:
http://thread.gmane.org/gmane.comp.freedesktop.xorg.drivers.ati/12433/focus=12444
Comment 5 Kjell Myksvoll 2010-04-02 12:04:44 UTC 
(In reply to comment #4)
> Does this patch help?
> http://git.kernel.org/?p=linux/kernel/git/airlied/drm-2.6.git;a=commit;h=383be5d1789d9a7a2e77dca1cb0aca89507d069e

Happy to try, but how should I do it? Shall I use the Ubuntu kernel source, apply the 6 patches to it, build and install the new kernel? Or is it possible to build the DRM moules outside of the kernel tree, using the DKMS or similar framwork?

Pointers are most welcome as I really would like to see a fix to this particular problem.
Comment 6 Kjell Myksvoll 2010-04-02 15:10:47 UTC 
(In reply to comment #4)
> Does this patch help?
> http://git.kernel.org/?p=linux/kernel/git/airlied/drm-2.6.git;a=commit;h=383be5d1789d9a7a2e77dca1cb0aca89507d069e

Hi,

Tried with the 2.6.34-rc3 kernel, which I noticed already had the patches added. Unfortunately there was no change. The distortion was exactly as before.

If it is of any interest I can upload the Xorg.0.log file, xdpyinfo output and the .config file for the build.

I am also happy to help with trying out other patches that might help.
Comment 7 Kjell Myksvoll 2010-10-23 08:56:57 UTC 
Hi,

Just to report that the distortion issues with the Radeon HD 4550 card (RV710) in combination with the Dell U2711 monitor is gone with the xserver-xorg-video-ati/xserver-xorg-video-radeon (ver. 6.13.1 according to 'apt-cache show') that got installed when I upgraded to the latest Ubuntu version (10.10/Merkat).

This is with acceleration and everything.

Great work!

br,
kmm

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