I was having similar problems to the folks in this thread with a samsung syncmaster SM23550AH. No or intermittent video, most recently when trying to get it working with a lenovo m720q displayport to hdmi dongle and then the same lenovo and a HP port replicator HDMI to the monitor. ultimately, I was able to get video on the svga connector with an old laptop. I ended up using windows 7 and svga to install the driver and firmware upgrade. heads up that the driver asked me if I wanted the analog or digital driver. I installed the digital- i think you can only do one or the other because rerunning...

I don't know why I need to do this, There are 2000+ pages of introductions that literally no one is going to read. me included. Just allow me to contribute to this wonderful knowledge base...