https://bugs.freedesktop.org/show_bug.cgi?id=76130
--- Comment #5 from Thaddäus Tintenfisch thad.fisch@gmail.com --- I'm also affected by this bug and I can confirm the performance hit after resuming the system from suspend.
Radeon HD 4330 + kernel 3.15.2
[ 4772.472528] [drm:rv730_stop_dpm] *ERROR* Could not force DPM to low [ 4772.954683] [drm] PCIE GART of 1024M enabled (table at 0x000000000025D000). [ 4773.002123] [drm] ring test on 0 succeeded in 1 usecs [ 4773.002180] [drm] ring test on 3 succeeded in 1 usecs [ 4773.187038] [drm] ring test on 5 succeeded in 1 usecs [ 4773.187042] [drm] UVD initialized successfully. [ 4773.187067] [drm] ib test on ring 0 succeeded in 0 usecs [ 4773.187089] [drm] ib test on ring 3 succeeded in 1 usecs [ 4773.337007] [drm] ib test on ring 5 succeeded [ 4773.507776] [drm:rv770_dpm_set_power_state] *ERROR* rv770_set_sw_state failed