Also try setting the monitor's input source (there's a button for that surely) to something other than 'Auto'. I fear Auto might be doing some active scanning and wake itself up when it comes back to the connector that you're using but wish to keep off.
Also try setting the monitor's input source (there's a button for that surely) to something other than 'Auto'. I fear Auto might be doing some active scanning and wake itself up when it comes back to the connector that you're using but wish to keep off.