What is actually going on inside these display adapters? My new iMac and extra displays occasionally fail to detect on waking, leaving an extra display black and in power-save mode. Could it be an adapter issue?
I’m curious whether there is much active electronic activity, power consumed, and so forth inside these things. For example, is there a constantly growing range of modes that some don’t support?
I have the same problem, and the short answer is yes to both (could be an adapter issue, and there is a growing range of modes that some don’t support). Just switching to a new HDMI cable solved my problem in one case.