My laptop has an ATI Radeon XPRESS 200M. Everything was working correctly on it with kernel-2.6.27.3-30.rc1.fc10.i686. With every kernel since then (I've tried -34 and -39), I've not been able to start X. When I boot with no extra kernel parameters, I just get a garbage pattern of horizontal lines on the screen when X starts. When I boot with "nomodeset", I get a black screen when X starts.

It seems that aside from the display, everything is working correctly. The laptop boots, I see the wireless light come on, when I hit the power button, I see the disk work for a bit and eventually the machine shuts down.

So it looks like just the display isn't working right.

lspci -vvv info for the display chip:

01:05.0 VGA compatible controller: ATI Technologies Inc Radeon XPRESS 200M 5955 (PCIE) (prog-if 00 [VGA controller])
	Subsystem: Hewlett-Packard Company Device 30ae
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 66 (2000ns min), Cache Line Size: 32 bytes
	Interrupt: pin A routed to IRQ 17
	Region 0: Memory at c8000000 (32-bit, prefetchable) [size=128M]
	Region 1: I/O ports at 9000 [size=256]
	Region 2: Memory at c0100000 (32-bit, non-prefetchable) [size=64K]
	[virtual] Expansion ROM at c0120000 [disabled] [size=128K]
	Capabilities: <access denied>
	Kernel modules: radeonfb, radeon

...other info available upon request. I may even be able to set it up so that I can ssh in while the display is in this state if it'll be helpful.

Some other (possibly unrelated) facts:

- on much earlier kernels, the display would be stuck at 640x480 unless I booted with "nomodeset". This seems to be fixed with -30 kernel. Possibly earlier ones, but I haven't tested this to determine when it was fixed.

- on the -30 kernel, while I can start X at the native screen resolution without using nomodeset, I can't hibernate the laptop. It writes data to the disk for a bit and then never actually powers off. When I boot with nomodeset, I can hibernate and resume it without any problem.