shturm at 
http://forums.fedoraforum.org/showthread.php?t=241902
reports the same problem and also indicates that 
"Upgrade to 2.6.32.9-70 did not help - I was getting the same errors (X crashes)."

Updated to 
xorg-x11-server-Xorg-1.7.5.901-1.fc12.i686.
It did not fix the problem.

Updated to 
2.6.32.9-70.fc12.i686
It did not fix the problem.
nomodeset makes things much worse.
Can login using tty4.
gdm log shows no problems.

Same here!  I have had to refuse the updates for kernels 2.6.31.12-174.2.22.

Same here!  I have had to refuse the updates for kernels *greater than* 2.6.31.12-174.2.22

1) Sometimes the system freezes before the login screen is reached.

2) If I'm quick enough after entering my password and pressing <Enter>, I can start tty4, wait until the disk stops making noise, and then return to tty1 with a working desktop. Logging out from this state usually freezes the system.

i'm facing the same problem as well...

No solution in sight. Have just increased the installonly_limit in yum.conf and waiting to see if anything comes around...

*** Bug 573400 has been marked as a duplicate of this bug. ***

I am having similar problems, except I have a nvidia TNT2 card and using the nouveau driver.

Should I submit as separate bug?

kernel: [drm] nouveau 0000:01:00.0: 32 MiB VRAM
kernel: agpgart-intel 0000:00:00.0: AGP 2.0 bridge
walden3 kernel: agpgart-intel 0000:00:00.0: putting AGP V2 device into 4x mode
kernel: pci 0000:01:00.0: putting AGP V2 device into 4x mode
kernel: [drm] nouveau 0000:01:00.0: 64 MiB GART (aperture)
kernel: [drm] nouveau 0000:01:00.0: Allocating FIFO number 0
walden3 kernel: [drm] nouveau 0000:01:00.0: nouveau_channel_alloc: initialised FIFO 0
kernel: [drm] nouveau 0000:01:00.0: Allocating FIFO number 1
kernel: [drm] nouveau 0000:01:00.0: nouveau_channel_alloc: initialised FIFO 1
kernel: [drm] nouveau 0000:01:00.0: nouveau_channel_free: freeing fifo 1
gdm-binary[1349]: WARNING: GdmDisplay: display lasted 1.421672 seconds
abrt[1442]: saved core dump of pid 1395 (/usr/bin/Xorg) to /var/cache/abrt/ccpp-1268758042-1395.new/coredump (2355200 bytes)

I got the same problem. I have a Lenovo T61p with the nVidia Quadro FX 570M (rev a1) using the xorg-x11-drv-nouveau-1:0.0.15-20.20091105gite1c2efd.fc12 (i686) and kernel version 2.6.31.5-127.fc12.i686.PAE.

I got it used, tore the windoze license sticker off and put Fedora 12 on. It took me about 6 reinstalls before I was able to figure out that this driver won't work with kernel 2.6.32.9-70.fc12.i686.

As long as I don't install the later kernel, x will start.

My problems have been resolved. 

My problem stems from the size of my monitor (2048x1152). Another monitor (1600x1200) worked OK.  The solution to my problem is not relevant to users with nvidia graphics. 

http://bugs.freedesktop.org/show_bug.cgi?id=27100.

Updated kernel to latest 2.6.32.10-90 and Xorg to 1.7.6-1 - the same problem remains - X crashes on startup.
Rolled back kernel to 2.6.31.12-174 - everything is fine.

For the folks with nVidia cards, make sure you remove any nomodeset from the kernel boot parameters. See bug 566619

kernel-2.6.32.11-99.fc12 has been submitted for testing but may not fix this bug.

Does abrt have any crashes saved? Open Applications | System Tools | Automatic Bug Reporting Tool or use the abrt-cli program to check.

no crashes saved in abrt. bug #566619 didn't help me too :( but I can boot with intel_iommu=off
Will try kernel-2.6.32.11-99.fc12

I have the same problem with my Dell Latitude D400 with an  Intel Corporation 82852/855GM Integrated Graphics Device rev 2. I'm stuck in  2.6.31.12-174. If I had a desktop, I'd replace the graphics card. With a laptop, I have no choice!

Updated kernel to latest 2.6.32.11-99 - the same problem remains - X crashes on startup.
Rolled back kernel to 2.6.31.12-174 - everything is fine.

2.6.32.11-99 has the same problem (see comment 16 above). I can log in okay with just the laptop screen enabled but it crashes in a couple of minutes. If I have the laptop screen and an external monitor enabled, it never displays the login prompt. 2.6.31.12-174 is not a solution, since the display freezes after an hour or so of use. I'm willing to help with testing, just let me know what I need to do.

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