My media player runs Ubuntu 12.10 with video drivers Gallium 0.4 on AMD RV710, experience standard. The graphics card is reported (lshw) as a Radeon HD 4350. This card is driving two displays. The first is a 17" Dell 4:3 monitor via DVI at around 800:600 pixels. This houses the Launcher and a few screenlets and always remains on. It is the only screen I have on at boot. The second display is an LCD 16:9 TV of 42" via HDMI at 1920:1080 pixels. This is switched on occasionally when required. The display is then extended so that the Dell is on the left and the TV the right, with the tops of each display aligned.
The problem occurs on transitions from switching the TV on or off - though the problem is more common when switching on from single to dual extended display. The symptom is that more often than not, when the TV is turned on, and the driver detects it, it corrupts the initialisation. Switching off and on again a few times fixes it. On rare occasions switching off causes the single display to be corrupted. Again, switching on and off again usually cures it in one. I had a similar problem in 12.04 until I finally got the dual head to work properly with the proprietary drivers, after which it worked consistently well.
So my question. As the driver is perfectly capable of initialising and running my two displays, why does it so often fail to do so, and is there anything I can do to make it work more consistently?