Originally posted by UniCav
I don't quite get the question. You set up your xorg.conf file and tell the Xserver what color depths and resolutions to use and set the default, then you use your desktop manager like KDE to choose which one you want. As for 'reading' the resolution there is tons of info in Xorg.0.log about what the graphics card and monitor are capable of and there are some other utilities like gtf that will calculate the exact modelines for your monitor.
I wasn't particulary clear was i?
The point was that there seems to be no way in KDE to affect the desktop colour-depth setting. Yes, a default can be set in xorg.conf but how is that changed from within a KDE session?
So far the only way I've seen is to close X, edit the default seting and restart X.
There is plenty of info on xorg and I'm happy enough to edit it manually but that is besides the point - KDE users can select from a range of desktop resolutions but have no control over colour depth without resorting to vi.