System Environment:
--------------------------

--Platform:i965

--Architecture(32-bit,64-bit,compatiblity):64bit 

--2D driver:
commit f69b48fe24ef94dac44b8123884ca71df675be4b

--3D driver:
commit b422e5ad3716d32f2434ca38819f4a877c7eeeeb

--Xserver:
commit 009f1e4e55200425de2fe0dbc1f0ac0f431fb4cf

--drm
commit b9417f41418321d5081547a3a3386dcccae7541f

--Kernel:
2.6.22-rc5


Bug detailed description:
-------------------------
startx ,run manywin 10 , it will hang system . and then turn off the TTM ,restart X ,this case will abort ,and print mesage 
" manywin: ../common/dri_bufmgr_fake.c:561: dri_bufmgr_fake_contended_lock_take: Assertion `((&bufmgr_fake->on_hardware)->next == (&bufmgr_fake->on_hardware))' failed.
Aborted
[root@x-g965 xdemos]# error setting MTRR (base = 0xc0000000, size = 0x10000000, type = 1) Invalid argument (22)
FreeFontPath: FPE "unix/:7100" refcount is 2, should be 1; fixing.
error setting MTRR (base = 0xc0000000, size = 0x10000000, type = 1) Invalid argument (22)"




Reproduce steps:
----------------
 run manywin 10



Current result:
----------------
abort,and hang system 


Expected result:
----------------
run normally