Downstream bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1019543

With my Radeon HD 7770 and the open radeonsi driver (on Kernel 3.11.x), I am
unable to output to an HDTV using HDMI. Only DVI works.

GNOME's display settings never "sees" the additional screen, and xrandr always
thinks that the HDMI port is disconnected, like so:


Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y
axis) 598mm x 336mm
   1920x1080      60.0*+
   1280x1024      60.0  
   1440x900       59.9  
   1280x800       59.9  
   1152x864       75.0  
   1024x768       70.1     60.0  
   800x600        60.3     56.2  
   640x480        66.7     60.0  
   720x400        70.1

Interestingly enough, this is not an issue if the HDMI cable was plugged in at
poweron/boot time instead of hotplugged: when cold-plugged, both screens are
turned on.

Some additional debug logs are available in the downstream report.
Please let me know how I can troubleshoot this.