This is for AMDGPU. I have an RX470 with two monitors attached via DP. After a long suspend, when one of the monitors has apparently gone into a deeper sleep state, it takes one of them longer to wake. When this happens, the second monitor is not detected and will not be seen until I switch to a VT and then back again. Here's what I see in dmesg before the switch: 18887.893100] [drm:amdgpu_atombios_dp_link_train] *ERROR* displayport link status failed [18887.893103] [drm:amdgpu_atombios_dp_link_train] *ERROR* clock recovery failed [18888.070075] [drm:amdgpu_atombios_dp_link_train] *ERROR* displayport link status failed [18888.070077] [drm:amdgpu_atombios_dp_link_train] *ERROR* clock recovery failed Again, after I switch to a VT and then back again, all is well.
Please attach your xorg log and dmesg output.
Created attachment 245461 [details] Xorg log
Created attachment 245471 [details] dmesg
Note that those two files were grabbed after I switched to a VT (since the UI was in a pretty whacked state.)
I should also note this is easily reproducible but still intermittent. I'd say 80% of the time, I see this. It's also not always one monitor - it can be either of them.
(In reply to Greg White from comment #5) > I should also note this is easily reproducible but still intermittent. I'd > say 80% of the time, I see this. It's also not always one monitor - it can > be either of them. Interesting. I have a very similar issue on Fiji (bug 176311) with two DP monitors, but in case of Fiji it is always one monitor that will be blank until the VT switch happens. And the error message is different.
I have attached a patch which seems to fix the problem here. Maybe it will be helpful?
Created attachment 246801 [details] Patch against atombios_dp.c Seems to fix the problem locally. I have no idea if it's correct or not, but it may help tracking down the actual problem. On my system, I see one training attempt when the monitors are on, 4-5 when they are in standby.