Any way to turn off external display output?

[stanft]

Hi everyone,

I have the following problem: I am giving courses at university with my rMBP. The rMBP is connected to a KVM switch which is forced to work in auto switch mode. So, as long as the rMBP sends a video signal to the external output (HDMI in this case) the KVM switch will always display the rMBP output.

In addition to the rMBP a stationary desktop PC is connected to the KVM switch. During the courses I have to switch display output between both the rMBP and the stationary PC. With my old Windows-based laptop this was not a problem because Windows allows you to turn off the external video signal using a key command (Win + P). Unfortunately, I have not found anything similar in OS X. The only way to turn off the signal (and make the KVM auto mode switch to the PC) is to pull the HDMI cable. Not a very nice solution.

I tried Switch Res X but unfortunately the application also is not able to turn off the signal completely.

Is there really no way to switch off the video signal by software or key command??

Best regards,
Stephan

 

[snaky69]

SwitchResX is supposed to work exactly for this purpose.

Honestly, why not just unplug it? It takes all of 0.5 seconds.

 

[stanft]

SwitchResX is supposed to work exactly for this purpose.

Honestly, why not just unplug it? It takes all of 0.5 seconds.

I tried SwitchResX but it didn't work very well on my rMBP. For example, when I switched the external (second) display off the external display goes into sleep mode (good) but the rMBP screen also goes black (bad). I had to perform a click in order to get the main display working again - and after that the external display was reactivated too (but showing only black).

Plugging in and out is not my favorite because every time I have to setup the resolution again (optimized for TV vs optimized for Retina).

 

[snaky69]

I tried SwitchResX but it didn't work very well on my rMBP. For example, when I switched the external (second) display off the external display goes into sleep mode (good) but the rMBP screen also goes black (bad). I had to perform a click in order to get the main display working again - and after that the external display was reactivated too (but showing only black).

Plugging in and out is not my favorite because every time I have to setup the resolution again (optimized for TV vs optimized for Retina).

If you left mirroring off, both screen could each have their own resolution and that problem would be solved.