Prebuffering Pause with MythTV on Radeon 9200 Dual-Head
 

I'm running MythTV on a dual-head system. The TV card is an Hauppauge WinTV PVR 150 (European - PAL) and the video card is an ATI Radeon 9200 SE. An Apple 20" cinema LCD display is connected to the DVI output (the primary) and a Sony CRT is connected to the VGA output (the secondary).

Xorg is configured to use the "radeon" driver, using the driver's "MergedFB" options. The two screens are set up as adjacent to each other (1024x768 and 1680x1050), giving a total resolution of 2704x1050, and pseudo-Xinerama mode is enabled. MythTV is configured to use only Xinerama screen 1, although I have tried it with screen 0 and both screens at the same time.

I'm running FC5 with the latest standard FC5 kernel, 2.6.16-1.2122_FC5. The drivers I'm using for the TV capture card are ivtv, 0.6.2 (the latest stable version, listed as being compatible with the 2.6.16 kernel).

My problem is this: when attempting to play live TV through MythTV, it's very jerky and every few seconds, the console prints "prebuffering pause", and the audio and video pause briefly and then catch up.

This never used to happen when I ran it in single-head mode. Can anyone suggest anything?

Regards
Davod