Comment # 2 on bug 955167 from Stefan Dirsch

Then why don't we see this issue also with NVIDIA drivers? AFAIK these are
lacking wayland support as well.

My guess is, that gdm somewhat detects the driver and disables wayland with
nvidia. But doesn't care about fglrx.

<osukup> panos: gdm -- by default starts wayland .. and fglrx doesnt support
wayland 
<osukup> panos: If you need to disable Wayland for GDM, edit
/etc/gdm/custom.conf to reflect the following:
<osukup> [daemon]
<osukup> WaylandEnable=false

--> Back to GNOME. They should know more about this behaviour.