==System Environment==
--------------------------
Regression: No. I didn't find good commit for this case.
platform: BSW

==kernel==
--------------------------
origin/drm-intel-nightly: 1113d085dfdba11c64772bfb4da26d1d3a163512(fails)
origin/drm-intel-next-queued: 985850bd145655d10dfcd5a03a3fc38540794ca7(fails)
origin/drm-intel-fixes: e3e6efcd638d3caa18d9e89f235c7d6fc32c1f0b(fails)

==Bug detailed description==
-----------------------------
nightly and next-queue have the same issue:

./gem_mmap_wc --run-subtest write-cpu-read-wc
IGT-Version: 1.9-g67eb20c (x86_64) (Linux: 3.18.0-rc7_drm-intel-next-queued_985850_20150111+ x86_64)
Test assertion failure function gem_set_domain, file ioctl_wrappers.c:366:
Failed assertion: drmIoctl((fd), ((((1U) << (((0+8)+8)+14)) | ((('d')) << (0+8)) | (((0x40 + 0x1f)) << 0) | ((((sizeof(struct drm_i915_gem_set_domain)))) << ((0+8)+8)))), (&set_domain)) == 0
Last errno: 2, No such file or directory
Subtest write-cpu-read-wc: FAIL (0.005s)

Issues on fixes branch is different:
 ./gem_mmap_wc --run-subtest write-cpu-read-wc
IGT-Version: 1.9-g67eb20c (x86_64) (Linux: 3.19.0-rc2_drm-intel-fixes_e3e6ef_20150111+ x86_64)
Test requirement not met in function test_write_cpu_read_wc, file gem_mmap_wc.c:274:
Test requirement: gem_mmap__has_wc(fd)
Subtest write-cpu-read-wc: SKIP (0.000s)



==Reproduce steps==
---------------------------- 
./gem_mmap_wc --run-subtest write-cpu-read-wc