I had problems using microHDMI port, too:
Using a 5m/17ft microHDMI -> HDMI cable made my system hang completely during handshake with my Onkyo AV receiver, xrandr didn't even show a new device on microHDMI port.
With a Samsung TV, handshake was a success and xrandr reported a fully funktionally display on the port, but turning the display on by 'xrand --auto', didn't gave me an image on Samsung TV. I believe this is because a low voltage on HDMI port AND high attenuation of this very cheap cable! (Motorola Xoom does work with this cheap cable)
I finally had success with a Hama microHDMI-HDMI adapter cable (15cm/6") plus a 1.5m/60" standard HDMI cable.
Did you try the Fn + F8 combo?
Originally Posted by peter rus
I'm using Openbox with gnome-settings-daemon (I believe, it's also default on Unity) atm, it works like a charm here just by using this combo...
If screen goes black (which is extremely rare), I just hit Fn+F8 for switching between following modes:
- eDP1 (embedded DisplayPort 1 == laptop display) single mode
- eDP1 cloning mode
- extended desktop -- eDP1 is primary
- external monitor single mode
It may also help, if you assign a key combo with a script similar to this:
...to re-enable it just in case of a black screen... ?
xrandr --output eDP1 --auto