(In reply to comment #4)
> I can confirm that I have a similar issue on 3.12.0. I have Asus K73TA
> laptop with AMD APU A6-3400M and a discrete card Radeon 6550M.
> 
> VGA Switcheroo device was created successfully with 3.11, but disappeared on
> 3.12.0. Error from dmesg:
> 
...

I think the issue went away in Kernel 3.12.2. Vgaswitcheroo in
/sys/kernel/debug 
does get created successfully and there are no "cut here" error traces in
dmesg.

Teo