I'm using:
2.6.29rc8 (actually git checkout from 20/03/2009)
xserver 1.6, mesa 7.3 and intel master also from git 20/03/2009

X worked fine until I wanted to log out from kde (using kdm):

(II) Open ACPI successful (/var/run/acpid.socket)
(II) APM registered successfully
(II) intel(0): [DRI2] Setup complete
(**) intel(0): Kernel mode setting active, disabling FBC.
(**) intel(0): Framebuffer compression disabled
(**) intel(0): Tiling enabled
(==) intel(0): VideoRam: -1 KB
(II) intel(0): Attempting memory allocation with tiled buffers.

Backtrace:
0: /usr/bin/X(xorg_backtrace+0x26) [0x4e9e76]
1: /usr/bin/X(xf86SigHandler+0x39) [0x48c9e9]
2: /lib64/libc.so.6 [0x7f2b5679f550]
3: /usr/lib64/libdrm_intel.so.1(drm_intel_bo_alloc+0x3) [0x7f2b54959663]
4: /usr/lib64/xorg/modules/drivers//intel_drv.so(i830_allocate_memory+0x306) [0x7f2b54b973b6]
5: /usr/lib64/xorg/modules/drivers//intel_drv.so(i830_allocate_2d_memory+0xc2) [0x7f2b54b981a2]
6: /usr/lib64/xorg/modules/drivers//intel_drv.so [0x7f2b54b8c5e3]
7: /usr/lib64/xorg/modules/drivers//intel_drv.so [0x7f2b54b91780]
8: /usr/bin/X(AddScreen+0x1c6) [0x42cdc6]
9: /usr/bin/X(InitOutput+0x242) [0x467ef2]
10: /usr/bin/X(main+0x20e) [0x42d4ce]
11: /lib64/libc.so.6(__libc_start_main+0xe6) [0x7f2b5678b5b6]
12: /usr/bin/X [0x42cb19]

Fatal server error:
Caught signal 11.  Server aborting