This is my issue and I wonder if it's the same.
https://ask.fedoraproject.org/en/question/45924/fedora-20-updated-hibernation-and-freezing-issue/

May  2 09:57:10 localhost kernel: [ 2668.206671] radeon 0000:01:00.0: GPU
lockup CP stall for more than 10000msec
May  2 09:57:10 localhost kernel: [ 2668.206684] radeon 0000:01:00.0: GPU
lockup (waiting for 0x000000000000000e last fence id 0x0000000000000002 on ring
5)
May  2 09:57:10 localhost kernel: [ 2668.206691] [drm:uvd_v1_0_ib_test] *ERROR*
radeon: fence wait failed (-35).
May  2 09:57:10 localhost kernel: [ 2668.206700] [drm:radeon_ib_ring_tests]
*ERROR* radeon: failed testing IB on ring 5 (-35).
May  2 09:57:10 localhost kernel: [ 2668.206738] [drm:radeon_pm_resume_dpm]
*ERROR* radeon: dpm resume failed
May  2 09:57:10 localhost kernel: radeon 0000:01:00.0: GPU lockup CP stall for
more than 10000msec
May  2 09:57:10 localhost kernel: radeon 0000:01:00.0: GPU lockup (waiting for
0x000000000000000e last fence id 0x0000000000000002 on ring 5)
May  2 09:57:10 localhost kernel: [drm:uvd_v1_0_ib_test] *ERROR* radeon: fence
wait failed (-35).
May  2 09:57:10 localhost kernel: [drm:radeon_ib_ring_tests] *ERROR* radeon:
failed testing IB on ring 5 (-35).
May  2 09:57:10 localhost kernel: [drm:radeon_pm_resume_dpm] *ERROR* radeon:
dpm resume failed