Comment # 101 on bug 73530 from Alex Deucher

Created attachment 115801 [details] [review]
leave panel power on all th time

(In reply to Nicolas Werner from comment #98)
> [    5.722365] [drm:radeon_dp_set_link_config] *ERROR* corrupt dpcd, updating
> [    5.722952] [drm] radeon_dp_set_link_config, ffff8802a1878c00, 540000, 1
> [    5.722953] [drm] dig_connector ffff8802a335fd60
> [    5.722954] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [    6.865341] [drm:radeon_dp_set_rx_power_state] *ERROR* corrupt dpcd,
> updating
> [    6.865932] [drm] radeon_dp_set_rx_power_state, ffff8802a1878c00, 0
> [    6.865933] [drm] dig_connector ffff8802a335fd60
> [    6.865934] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [    8.001613] [drm:radeon_dp_link_train] *ERROR* corrupt dpcd, updating
> [    8.002284] [drm] radeon_dp_link_train, ffff8802a1878c00
> [    8.002285] [drm] dig_connector ffff8802a335fd60
> [    8.002287] [drm] DPCD: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [    8.002287] [drm] dp_info dpcd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00

For some reason the DPCD reads back unreliably.  It's all zeros the first few
times.


> [    8.002289] [drm:radeon_dp_set_rx_power_state] *ERROR* corrupt dpcd,
> updating
> [    8.002594] [drm] radeon_dp_getdpcd ffff8802a1878c00
> [    8.002595] [drm] dig_connector ffff8802a335fd60
> [    8.002595] [drm] DPCD: 11 0a 02 00 00 00 00 00 00 00 00 00 00 00 00

Finally it reads back correctly, but at this point it's too late.


> [    8.002597] [drm] radeon_dp_set_rx_power_state, ffff8802a1878c00, 17
> [    8.002598] [drm] dig_connector ffff8802a335fd60
> [    8.002599] [drm] DPCD: 11 0a 02 00 00 00 00 00 00 00 00 00 00 00 00
> [    8.010706] [drm:radeon_dp_link_train_cr] *ERROR* clock recovery tried 5
> times
> [    8.010707] [drm:radeon_dp_link_train_cr] *ERROR* clock recovery failed

Does this patch help the reliability any?