https://bugs.freedesktop.org/show_bug.cgi?id=71083
--- Comment #1 from Alex Deucher agd5f@yahoo.com --- Are you unplugging the cable from the card when you switch the monitors? That should generate a hotplug event which will trigger the graphics stack to reprobe the displays. If you are just changing the monitor connected to the receiver, it sounds like the receiver never sends a hotplug event to the card. As such the card has no way of knowing that the EDID has changed.