Configuring XFree86 for new Tibook (Radeon Mobility 7500)

[Steve Penn]

I have a new TiBook and have been unable to get XFree86 to configure
correctly.  The video card is an ATI Radeon Mobility 7500 and the screen is
1280x854.

Note that XFree86 is installed on Mac OS X and it drives the screen fine.
However  I think that it makes use of the Apple/ATI driver since it does not
use any XF86config file.

My attempt to configure XFree86 properly involved running Xconfigurator and
selecting the old Tibook screen (1152x768 driven by Radeon Mobility). Of
course this does not select the correct driver. I then ran

> XFree86 -config

to get the proper card ID, which it puts in the file XFree86Config.new

Finally I edited the configure file (/etc/X11/XF86Config-4) and inserted the
Card0 lines that were generated in the file XFree86Config.new

In the Monitors section of XF86Config-4  are the various monitor
configurations.  Below the line for the old Powerbook G4 I entered a new
line for new Powerbook G4.  My guess is that the frequencies listed are
diagonal, horizontal and vertical.  I adjusted the diagonal frequency until
the basic screen geometry was right.  My best guess was 79.55. I chose the
other H & V numbers using linear scaling from the old Powerbook G4 numbers.
Since I don't know what the other H & V numbers do, I don't think that my
method is right and I think these numbers are likely the reason why the
screen is not quite right. The screen appears ok but there were horizontal
hash lines in four bands.

Does anyone know what the set of H & V frequencies represent and how we
might arrive at the best values for these?

I put the Modelines from my XF86Config-4 file below:

# Powerbook G4
# D: 64.994 MHz,  H: 44.154 kHz, V: 54.781 Hz
Modeline "1152x768" 65 1152 1178 1314 1472  768 771 777 806 +HSync +VSync

# New Powerbook G4  1280x854
Modeline "1280x854" 80 1280 1309 1460 1636  854 857 864 896 +HSync +VSync


Thanks very much,
Steve Penn  (penn@phy.syr.edu)