My powerbook 1.5ghz April '04 has problem with the LCD 
frequency/timings, in fact XF86Config won't acquire the display 
correctly.
Of course when I boot using the external monitor everthing works ( not 
so well but X works ).
First i want to know if someone owning the same powerbook has managed 
to start X; then I hope he will send me his XF86Config.
The same problem ( I suppose ) has occured to me under linux2.6.8 
kernel and previouses until a kernel patches 2.6.9.rc2bkXX ( rc3 
contains the patch ) has solved the problem
Here it is the patch description.
<benh@kernel.crashing.org>
	[PATCH] radeonfb: Fix newer PowerBook & warnings
	
	This fixes a few warnings in radeonfb and add proper PLL divider values
	for Apple latest PowerBook Aliminium 17" so the display isn't "fuzzy"
	(the LVDS interface needs special PLL values that the driver can't
	calculate, on most x86, the BIOS tells us the values to use, on Apple
	laptops, we have to hard code them for each model).
	
	Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
	Signed-off-by: Linus Torvalds <torvalds@osdl.org>

I don't know how to help anymore
Francesco