I get the same issue with my iMac and MacBook Air, after the firmware upgrade its a lot better but still happens randomly. The more I unplug and plug back in the quicker it is to just drop out - so restarting sometimes helps me there.
I guess just double check the connections between your mac and dingoo, mine always hangs on when I disconnect. Always have to hit the reset button for it to come back to life.
Need to figure out if its the mac software or firmware causing the issue.