Since Yosemite HDMI not working??

[bbishop93]

So I have a 15inch rMBP and I literally would use my HDMI every day then after Yosemite for some reason when I plug it in my macbook screen turns like a dark blue blank screen and the external display is also blank. But I cannot do anything, if I unplug the cable, my macbook screen still stays that blank dark blue screen and I can't do anything but turn it off and back on...Any suggestions? I already tried resetting the pram and tried using command + F1 to change the display mode when plugged in. IDK what else to do...

 

[someoneoutthere]

So I have a 15inch rMBP and I literally would use my HDMI every day then after Yosemite for some reason when I plug it in my macbook screen turns like a dark blue blank screen and the external display is also blank. But I cannot do anything, if I unplug the cable, my macbook screen still stays that blank dark blue screen and I can't do anything but turn it off and back on...Any suggestions? I already tried resetting the pram and tried using command + F1 to change the display mode when plugged in. IDK what else to do...

Does it have a dGPU? If it does, make sure that you are not forcing your MBP to use iGPU over gfxcardstatus app.
I wasted 15 minutes the other night trying to connect my rMBP via HDMI to a Smart TV, and it didn't work 'till I changed it back to dGPU.

 

[bbishop93]

Does it have a dGPU? If it does, make sure that you are not forcing your MBP to use iGPU over gfxcardstatus app.
I wasted 15 minutes the other night trying to connect my rMBP via HDMI to a Smart TV, and it didn't work 'till I changed it back to dGPU.

How do I change this to make sure it always chooses the dedicated GPU? Also isn't it weird that when I unplug the hdmi my macbook still has that blue blank screen...? I feel like that shouldn't happen...

 

[someoneoutthere]

How do I change this to make sure it always chooses the dedicated GPU? Also isn't it weird that when I unplug the hdmi my macbook still has that blue blank screen...? I feel like that shouldn't happen...

Your computer does it automatically for you, unless you use that app named gfxcardstatus - if you have the MBP with dedicated graphics card that is.
Speaking of the blue blank screen... One of your graphics card could be shot.
Why don't you click on the Apple icon (top left corner) --> About This Mac --> System Report --> Graphics and Displays and see if there's something wrong there?
I am far from being an expert on anything but I would look there first.

 

[bbishop93]

Your computer does it automatically for you, unless you use that app named gfxcardstatus - if you have the MBP with dedicated graphics card that is.
Speaking of the blue blank screen... One of your graphics card could be shot.
Why don't you click on the Apple icon (top left corner) --> About This Mac --> System Report --> Graphics and Displays and see if there's something wrong there?
I am far from being an expert on anything but I would look there first.

Yeah I tried setting it to one...not luck. I tried SMC reset and restarting with the HDMI cable in, when I do that yosemite loading bar freezes like 1/5 of the way after I login.