Michel Dänzer wrote:
2) When I reduce the display resolution the display is reduced to the top-left, and surrounded by garbage. I suspect the frame buffer driver is missing something to enable the scaling hardware in the chip.Correct. The X server driver can basically do it if you don't use Option "UseFBDev", but not correctly either because we don't have an equivalent for a video BIOS providing the necessary information.
About the DGA thing: DGA has to be one of the most useless and incorrectly used extensions. If xmame doesn't work without it, I'd consider it broken.
xmame works fine in a window, but doesn't do full-screen without it. I started down this track because I wanted to see if the hardware scaling would work better than xmame's software scaling.
-- Adrian Cox http://www.humboldt.co.uk/