Hello, I have my openSUSE 42.2 LEAP on a MacBook Pro Mid 2012 no retina model and my problem is that I can’t use an external monitor, when I connect my VGA adapter to the minidisplay port nothing happens, KDE do not detect the screen and I know that it works because in macOS it works weel (I use linux for development).
To help with an answer my leap 42.2 install hasn’t detected my hdmi output. A YAST hardware probe doesn’t detect it either, only my graphic’s card main output - doesn’t matter to me but mentioned as I am not running it in a VM - the OP may be by the sounds of it.
I can only assume that the graphics card will handle it automatically if something is plugged into the hdmi port. Sorry can’t try that.
It was just before midnight when I posted so I should correct what I stated really. The main point was that are you running leap via a dual boot or via something like virtual box ?
YAST shows my hdmi output as well which shows that the kernel is detecting it during boot. I also have an on board sound plus an actual sound care which is the one I use. It’s not unusual for the install to pick the wrong default. Are you running kde for your desktop? It might be better to look at what it reckons you have before trying changes in YAST.