[SOLVED] Another ATI odissey: dual head with xrandr

Question

OK folks, say "Thanks!" to ATI for keeping the forum activity sky-high...
Let's start from the beginning: I have aSony Vaio VGN-SR21M/S laptop which sports an ATI Mobility Radeon HD3470, I use it at work and I love the dual monitor setup. Things worked beautifully with xorg-server 1.5 and catalyst 9.1, so I even wondered why so many people complains about ATI stuffs under Linux. But then xorg-server 1.6 came...
At first, I sticked with catalyst 9.4 from AUR, single and dual monitor worked (even if holding down a key made the X server crash when using dual monitor). After an upgrade (don't remember which one) catalyst refused to work, causing a segfault when starting X (the infamous signal 11 which fills the forums in these days). I tried to recompile the drivers, to reinstall the server, but nothing worked, so I decided to switch to the open xf86-video-ati driver.
The open driver works pretty well with single screen, but dual screen is driving me mad. Here's my xorg.conf:
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 0 0
EndSection
Section "Device"
Identifier "Card0"
Driver "radeon"
Option "monitor-VGA-0" "VGA"
Option "monitor-LVDS" "LVDS"
EndSection
Section "Monitor"
Identifier "VGA"
Option "PreferredMode" "1280x1024"
Option "RightOf" "LVDS"
EndSection
Section "Monitor"
Identifier "LVDS"
Option "PreferredMode" "1280x800"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "LVDS"
DefaultDepth 24
SubSection "Display"
Modes "1280x800"
Depth 24
Virtual 2560 1024
EndSubSection
EndSection
and here's the output of xrandr:
$ xrandr
Screen 0: minimum 320 x 200, current 2560 x 800, maximum 2560 x 1024
VGA-0 connected 1280x800+1280+0 (normal left inverted right x axis y axis) 0mm x 0mm
1280x800 59.8*
1024x768 60.0
800x600 60.3
640x480 59.9
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1280x800 59.8*+
1280x720 59.9
1152x768 59.8
1024x768 60.0 59.9
800x600 60.3 59.9
640x480 59.9 59.4
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 disconnected (normal left inverted right x axis y axis)
Screens seem ccorrectly configured, but the laptop LCD (LVDS) is blank. I can switch screens off and switch output, but can't make them work at the same time. I tried to remove the static configuration and tried to do everything manually using xrandr, but with the same results.
I don't know if it is a driver issue (so maybe switching to radeonhd could solve the problem) or an xorg bug...
Can anyone give me some useful hint? Thanks
Last edited by snack (2009-04-25 19:28:57)

Answer 1

Solved. Using radeonhd instead of ati makes everything as smooth as possible. The above xorg.conf works perfectly (substituting the monitor names used by ati with those used by radeonhd). I think that the problem is R600 support in ati, which is admittedly experimental and incomplete. Hope this can help someone...