I’m beginning to think the LVDS interface on XPRESS chips is dual purpose like the FP2 interface on avivo chips. If you have a desktop XPRESS chip with with DVI-D that’s not working with the current ati driver in git (or a recent 6.7.19x release), please add the following lines to the device section of your xorg.conf and test the driver:
Option “ConnectorTable” “1,2,2,1,1,1,2,2″
Option “PanelSize” “1280×1024″
Change “1280×1024″ what whatever size your panel is.