I'm having lots of trouble with a very simple setup (kernel, libdrm, radeon and other stuff are all rather recent from git).
I'm using an HD 4550. I have a main 1920x1080 monitor as DVI-0. On its own, it works perfectly. The trouble starts when I plug in a Samsung 1280x720 TV as HDMI-0.
First of all, the only common resolution they have is 640x480, which is what KDM uses. It's selected regardless of whether the TV is on or off, as it reads it via HDMI. It's not only ugly, but it keeps this resolution after logging in. Then I have to do "xrandr --output HDMI-0 --off" and "xrandr -s 1920x1080" and resize all the panels which were not designed for 640x480. Very annoying, since I only want to use the TV occasionally for watching a movie.
I've tried solving it by putting the relevant xrandr calls into /usr/share/config/kdm/Xsetup, but this didn't work well (right resolution, wrong DPI, and a tiled 640x480 wallpaper).
The current solution is the manually plug and unplug the HDMI cable based on whether I need to use the TV, which works fine once KDE and X are up and running, but can't be the long-term solution.
How can I get a 1920x1080 framebuffer console at boot, like I do with a single monitor? How can I switch off the HDMI-0 output BEFORE kdm starts, so it can set the native resolution of my main monitor instead of 640x480?