No signal?

[teckau]

Hi,

I have problems getting any 4k here. My setup is a late 2012 mac mini, HDMI connection to a SAMSUNG TV (HDMI 2.0) and a cable that is working with my AV receiver in 4k resolution.

When I patch the IOkit and reboot the mac is recognizing my 4k TV with a native 4k resolution, VNC is switching to 4k but the TV stays blank. I can switch back and forth between HD and UHD several times before my mac becomes unresponsive. Then, I have to boot into recovery mode and move the IOkit.bak to IOkit. The mac will not work anymore (neither TV nor VNC) before moving that file back.

Any idea? I am really not having a clue what's going on here... Thank you! Cheers

[teckau]

Just a clarification: I patch the IOkit successfully -> reboot -> sytem settings -> monitors -> standard resolution for monitor -> screen goes blank on HDMI while a parallel VNC session changes to UHD. I cannot switch back using the system settings window (doesn't do anything), but using switchresx I can switch back to 1080p60 and instandly the TV is showing a signal again. switchresx -> UHD -> VNC resizes again, TV does go black again -> repeat this 3-4 times -> OS X entirely goes "bad", windowsServer dies and the system becomes unresponsive...

[Floris497]

that is interesting.. I had this problem before i think.. It was fixed by disconnecting and reconnecting the HDMI.. But I'm not sure what really fixed it for me.. But it was a problem with my AOC monitor..

[jasonhugo]

I have exactly the same problem with my 2012 mac mini and a Samsung 4k tv. I'm actually quite relieved to find your comment because i thought something was wrong with my setup. If you find a solution please let me know.

[Floris497]

Have the same aoc display? I got a new display :) but not sure if that was the full problem.. I am now running an gtx 670 on my mini via thunderbolt :D

[teckau]

I could not find any solution and I am thinking that it very well might be related to the SAMSUNG TV itself. @jasonhugo: What model do you have? I am using a 65" European model (upgraded with the latest EvoKit SEK-3500 I guess).

Ordered a mDP 1.2 to HDMI 2.0 active adapter on Amazon and awaiting it to be delivered today. After testing with this device I'll leave another comment.

[jasonhugo]

It's a Samsung 48JU6000 (European model). It'll be interesting to see how the adapter goes - that's pretty much my next option.

[Floris497]

Did you get the adapter already? Hope that fixed the issue..

[teckau]

Unfortunately I still did not get the adapter by now. It was an Amazon marketplace sub and the information provided was not accurate about the delivery date. But it should be here on Monday, though.

Like I said I'll get back to that as soon as I will have had the chance to test. Thanks guys, it feels better to have someone to talk things over even if this does not solve the issue itself ;)

[Floris497]

Can you provide me a link of the product you bought?

[teckau]

Sure, go to Amazon and search for "Club 3D CAC-1170". Maybe this link will also do it: http://www.amazon.de/Club-3D-CAC-1170-DisplayPort-Adapter/dp/B017BQCUGW/ref=sr_1_1?ie=UTF8&qid=1461504323&sr=8-1&keywords=Club+3D+CAC-1170

[Floris497]

Yes, that's the only good one out there as far as i know

[teckau]

Still sorry for not updating my own thread but amazon didn't deliver today either. This marketplace seller sucks but I am still hoping to receive the item tomorrow and I am going to post the results of my test, too!

[Floris497]

We'll hear when you got time to test it and received the adapter :)

[teckau]

Ok, so the adapter has arrived and I've played around with it a little bit. It does work, the screen resolution of 4k@30Hz is selectable (automatically selected when choosing the screen native resolution option). But there are some drawbacks: First you will notice that 30 Hz is good enough to have fun with your holiday pictures but not good enough to even use the UI (scrolling is to slow and ugly). Second, I do have "glitches" which might be related to my cable (will check this another day). And third, the most annoying thing: The top down menu suddenly disappears, reappears in slushy green or red instead of black and is mostly not visible at all. This seems to be application related as VMware Fusion does display its menu items always visible and in black while iTunes e. g. does almost always display nothing. After iTunes started there is a red or green menu but it disappears suddenly after a short while (may be related to mouse overs or general actions). This is really ugly.

And BTW: Even on a 65" screen and just 1.5m distance the native resolution w/o HiDPI does not work for my eyes ;) You will need SwitchResX zu select 1080p30/HiDPI to make the resolution usable...

Any comments? Anything I should test?

[jasonhugo]

Thanks for getting back to us. It appears an adapter gets us half way there. Hopefully Floris497 can shed some light on the niggles you are having.

[Floris497]

Can you provide a screenshot of the arteffects?

This is the point where your hardware is able to do it.. But isn't really powerful enough to do it.. The reason why Apple doesn't allow it..

It can also be a problem with the framebuffer.. But how to solve that.. I have no idea at this point..

I'll read back this thread later to see if I can tell something more interesting/useful about it