I use Fedora 20. I have an HD7950 card driving three monitors. When using the open source AMD drivers with glamor acceleration, my X display is corrupted on first startup. It looks like this: http://imgur.com/PqOAGyB
When I restart X (ctrl-alt-backspace), the system seems to "think" for a while (the monitors go into sleep mode), and then after a minute or so the display comes up fine. Subsequent restarts of X work fine as well.
Here is the Xorg.0.log for the first (corrupted display) start: https://gist.github.com/rocketraman/9586629
Here is the Xorg.0.log for the second (good display) start: https://gist.github.com/rocketraman/9586639
The biggest diff between the two logs seems to be that on the first start there is some strange output for a "RADEON(G0)" which does not exist on the second log.
With glamor acceleration disabled, the X server starts normally.
Can anyone help?
$ glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD TAHITI
OpenGL version string: 2.1 Mesa 10.0.3
OpenGL shading language version string: 1.30
$ rpm -q xorg-x11-server-Xorg
$ rpm -q xorg-x11-drv-ati
$ rpm -q xorg-x11-glamor