Description of problem:
With the kernel 2.3.27.15-170 X doesn't starts.
/var/log/mesages show:

Feb 20 01:06:19 localhost kernel: mtrr: base(0xf0fc8000) is not aligned on a size(0x640000) boundary
Feb 20 01:06:19 localhost kernel: executing set pll
Feb 20 01:06:19 localhost kernel: executing set crtc timing
Feb 20 01:06:19 localhost kernel: [drm] DAC-6: set mode 1280x960 1b
Feb 20 01:06:47 localhost kernel: [drm:radeon_gem_ib_get] *ERROR* Major case fail to allocate IB from freelist ffff
Feb 20 01:06:47 localhost kernel: [drm:radeon_cs2_ioctl] *ERROR* ib_get failed
Feb 20 01:06:51 localhost kernel: [drm:radeon_gem_ib_get] *ERROR* Major case fail to allocate IB from freelist ffff
Feb 20 01:06:51 localhost kernel: [drm:radeon_cs2_ioctl] *ERROR* ib_get failed
Feb 20 01:06:51 localhost kernel: [drm:radeon_gem_ib_get] *ERROR* Major case fail to allocate IB from freelist ffff
Feb 20 01:06:51 localhost kernel: [drm:radeon_cs2_ioctl] *ERROR* ib_get failed
Feb 20 01:06:51 localhost kernel: [drm:radeon_gem_ib_get] *ERROR* Major case fail to allocate IB from freelist ffff
Feb 20 01:06:51 localhost kernel: [drm:radeon_cs2_ioctl] *ERROR* ib_get failed

and contine for ever

Version-Release number of selected component (if applicable):

Linux version 2.6.27.15-170.2.24.fc10.x86_64 (mockbuild.redhat.com) (gcc version 4.3.2 20081105 (Red Hat 4.3.2-7) (GCC) ) #1 SMP Wed Feb 11 23:14:31 EST 2009

xorg-x11-drv-ati-6.10.0-2.fc10.x86_64


How reproducible:
Every time

Steps to Reproduce:
1.At Boot 
  
Actual results:
The system show a arrow cusor,the cursor respond slowly to the mouse movements and you need to restart the machine


Expected results:

Normal boot

Additional info:

I can boot the machine with the kernel 2.6.27.5-117.fc10.x86_64

I have submitted a bug similar for previous versions of the kernel 
https://bugzilla.redhat.com/show_bug.cgi?id=476202