Latest git driver/xserver, Xorg gives me: 

X.Org X Server 1.5.99.1
Release Date: 5 September 2007
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.25.4-30.fc9.i686 i686 
Current Operating System: Linux memory 2.6.25.4-30.fc9.i686 #1 SMP Wed May 21 18:12:35 EDT 2008 i686
Build Date: 11 June 2008  10:06:36AM
 
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Wed Jun 11 10:22:42 2008
(==) Using config file: "/etc/X11/xorg.conf"
Aborted

Running it through gdb, this is what I get:

X.Org X Server 1.5.99.1
Release Date: 5 September 2007
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.25.4-30.fc9.i686 i686 
Current Operating System: Linux memory 2.6.25.4-30.fc9.i686 #1 SMP Wed May 21 18:12:35 EDT 2008 i686
Build Date: 11 June 2008  10:06:36AM
 
	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Wed Jun 11 10:23:00 2008
(==) Using config file: "/etc/X11/xorg.conf"
[New Thread 0xb80216c0 (LWP 25610)]
[tcsetpgrp failed in terminal_inferior: Operation not permitted]

Program received signal SIGABRT, Aborted.
0x00110416 in __kernel_vsyscall ()
Missing separate debuginfos, use: debuginfo-install xorg-x11-server.i386
(gdb) bt
#0  0x00110416 in __kernel_vsyscall ()
#1  0x003f7660 in raise () from /lib/libc.so.6
#2  0x003f9028 in abort () from /lib/libc.so.6
#3  0x004345bd in __libc_message () from /lib/libc.so.6
#4  0x0043a7e4 in malloc_printerr () from /lib/libc.so.6
#5  0x0043c846 in free () from /lib/libc.so.6
#6  0x001fcdae in CailReleaseMemory (CAIL=0x8492110, addr=0x8483360)
    at radeon_atombios.c:2039
#7  0x001f9dcb in ReleaseMemory (pDeviceData=0xbfa432f4, 
    pWorkingTableData=0x8483360) at AtomBios/hwserv_drv.c:303
#8  0x001f9b3a in ParseTable (pDeviceData=0xbfa432f4, 
    IndexInMasterTable=<value optimized out>) at AtomBios/Decoder.c:199
#9  0x001fdc0e in ParseTableWrapper (pspace=0xbfa433bc, 
    index=<value optimized out>, handle=0x8492110, BIOSBase=0xb7f60008, 
    msg_return=0xbfa43338) at radeon_atomwrapper.c:50
#10 0x001fb258 in rhdAtomExec (handle=0x8492110, unused=ATOMBIOS_EXEC, 
    data=0xbfa433b0) at radeon_atombios.c:1946
#11 0x001fb3b5 in RHDAtomBiosFunc (scrnIndex=0, handle=0x8492110, 
    id=ATOMBIOS_EXEC, data=0xbfa433b0) at radeon_atombios.c:1988
#12 0x00212c68 in atombios_dac_detect (pScrn=0x8484eb8, output=0x84987d0)
    at atombios_output.c:1019
#13 0x001f343a in radeon_detect (output=0x84987d0) at radeon_output.c:397
#14 0x001d0df2 in RADEONPreInitControllers (pScrn=0x8484eb8)
    at radeon_driver.c:2610
#15 0x001d2b3f in RADEONPreInit (pScrn=0x8484eb8, flags=<value optimized out>)
    at radeon_driver.c:2899
#16 0x080a9197 in InitOutput (pScreenInfo=0x81ed700, argc=1, argv=0xbfa43854)
    at xf86Init.c:745
#17 0x0806cde1 in main (argc=1, argv=0xbfa43854, envp=0xbfa4385c) at main.c:338

git-bisect gives me:

09eb220971b5d2bfd7d1ff6f552060967a133152 is first bad commit