Comment 133 for bug 745112

Running

xrandr --output DP1 --mode 2560x1600 --above LVDS1 --set audio on

when it's previously working does immediately make the monitor black out, and using '--set audio off' does not bring it back, nor does soft power cycling the monitor or unplugging/replugging it.

I can see some reports of people complaining about dp/audio problems under windows with the U3011, but it's hard to tell how much they indicate a real hardware/firmware problem vs windows driver problems or something else.

http://en.community.dell.com/support-forums/laptop/f/3517/p/19370516/19844480.aspx

> It seems that the Nvidia based implementation at least with Displayport "++" out will only support an audio signal being passed over displayport to an external monitor that is no high resolution than 1080HD, or 1920x1080.

So I wonder if there is some way for Linux to know not to try this, preferably without needing special user configuration:

 * don't do audio above a certain resolution?
 * ... on specific hardware models?
 * don't do DP audio at all by default?