https://bugs.freedesktop.org/show_bug.cgi?id=73530
--- Comment #89 from Nicolas Werner nicolas.werner@ymail.com --- (In reply to Alex Deucher from comment #88)
Created attachment 115774 [details] [review] add some debugging output
Can you attach your dmesg output with this patch attached? It should help narrow down where the dpcd info is getting corrupted.
Here it is (only the relevant section): [ 5.534907] [drm] radeon_dp_getdpcd [ 5.534913] [drm] DPCD: 11 0a 84 01 00 0b 01 01 02 00 00 00 00 00 00 [ 5.565816] [drm] fb mappable at 0xD047B000 [ 5.565823] [drm] vram apper at 0xD0000000 [ 5.565825] [drm] size 8294400 [ 5.565828] [drm] fb depth is 24 [ 5.565830] [drm] pitch is 7680 [ 5.566022] fbcon: radeondrmfb (fb0) is primary device [ 5.566093] [drm] radeon_dp_set_link_config, 270000, 2 [ 5.566095] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 6.706063] [drm] radeon_dp_set_rx_power_state, 0 [ 6.706065] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 7.843201] [drm] radeon_dp_link_train [ 7.843203] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 7.843204] [drm] dp_info dpcd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 7.843206] [drm] radeon_dp_set_rx_power_state, 0 [ 7.843206] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00