Comment 47 for bug 22976

Forwarding this bug from a Ubuntu user (other users report similar behavior on various iMac flavors):
https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/22976

"I found two problems:

1. The BusID was set to PCI:6:3:0 in xorg.conf - it should have been PCI:0:16:0.

2. Even with the correct BusID in xorg.conf the sync freqs were not probed correctly.

Here are the changes I had to make to xorg.conf to get X started:

--- xorg.conf.orig 2008-04-17 05:48:45.820016000 +0000
+++ xorg.conf 2008-04-17 06:53:33.362385848 +0000
@@ -31,12 +31,14 @@

 Section "Device"
        Identifier "Configured Video Device"
- BusID "PCI:6:3:0"
+ BusID "PCI:0:16:0"
        Option "UseFBDev" "true"
 EndSection

 Section "Monitor"
        Identifier "Configured Monitor"
+ HorizSync 60-60
+ VertRefresh 75-117
 EndSection

 Section "Screen"

Here is the original Xorg.0.log file from the live cd before changing xorg.conf:
http://launchpadlibrarian.net/13534788/Xorg.0.log