Experimenting modesetting in radeon driver

[Henry Zhao]

I treawked randr code a little bit (both in server layer and xfree86 
layer), and added RADEONDriverFunc() with a new function type
RR_PROBE_MODE to radeon driver to reprobe monitor configuration and
reinitialize modes, then I was able to do limited modesetting adapting
monitor changes.

Triggered by randr command or screen resolution change in GNOME, I
was able to successfully change modes with the following sequence:
(note the sequence starts from single mode)

single mode -> merged mode (adding a monitor) -> single mode
(removing a monitor) -> merged mode (adding a monitor) -> ...

However, if I started the sequence from merged mode:

merged mode -> single mode (removing a monitor)

then the screen got garbled. Check the log file for mode numbers
nothing appeared wrong.

Anyone can shed light on what's wrong here ? Thanks.


-Henry