When I posted Dual Head on Fedora 11 last night, I thought I had the problem completely solved, but when I booted the system this morning, the video card was acting up again. There were lots of black horizontal streaks through the display, and the server crashed in short order. Rebooting again got the same results. I’ve seen this behaviour previously with this card (VisionTek Radeon HD 2600 Pro AGP dual DVI), but since it was working OK last night I thought whatever bug had caused it was long since squashed. Apparently not.
I replaced the card with an older Sapphire Radeon X1950 Pro AGP 256MB dual DVI card, and it did not exhibit the same problem. However, now when I moved windows over to the right side of the right monitor, they also overlapped the left side of the left monitor. The X server defaulted to a desktop to 2560×1600, while my side-by-side monitors need 3520×1200. Another tweak to the xorg.conf, and now it works correctly. Also, the radeon driver supplied with Fedora 11 has 3D acceleration support for the X1950, but not for the HD2600, so I’m better off with the older card for now.
The updated xorg.conf is below.
# Xorg dual-head configuration # monitors: Samsung SyncMaster 213T and Dell 2405FPW # card: Visiontek Radeon HD 2600 Pro 512MB AGP Dual-DVI (RV630) or # or Sapphire Radeon X1950 Pro 256MB AGP Dual-DVI (RV570) # Eric Smith# $Id: xorg.conf,v 1.2 2009/09/19 06:05:56 eric Exp eric $ Section "ServerLayout" Identifier "Default Layout" Screen 0 "Screen0" 0 0 InputDevice "Keyboard0" "CoreKeyboard" EndSection Section "InputDevice" # keyboard added by rhpxl Identifier "Keyboard0" Driver "kbd" Option "XkbModel" "pc105+inet" Option "XkbLayout" "us" EndSection Section "Device" Identifier "Videocard0" Driver "radeon" Option "monitor-DVI-0" "Dell" Option "monitor-DVI-1" "Samsung" EndSection Section "Monitor" Identifier "Dell" # Dell 2405FPW # Without the PreferredMode option, the X server # decides to use 1600x1200. Option "Preferredmode" "1920x1200" EndSection Section "Monitor" Identifier "Samsung" # Samsung SyncMaster 213T # The PreferredMode option doesn't seem to be # necessary here, as the X server picks # 1600x1200 on its own. # Option "Preferredmode" "1600x1200" Option "LeftOf" "Dell" EndSection Section "Screen" Identifier "Screen0" Device "Videocard0" Monitor "Dell" DefaultDepth 24 SubSection "Display" # Without the following Virtual specification, the server # will default to 2560x1600 when using the Radeon X1950 card, # causing overlap of windows at the far right with the far # left. Virtual 3520 1200 Viewport 0 0 Depth 24 EndSubSection EndSection