After the upgrade to Mac OS X Yosemite I can no longer use the 4K resolution on my Mac Mini 2012. The option for the 3440 x 1440 resolution is just no longer available. So my LG 34um95 4K display is currently not a 4K display. It seems that I am not the person in this world that this problem. Other Mac users have the same problem. According to this thread on an Apple forum there is a solution to the problem. Use the old Mac OS X Maverick AppleIntelFramebufferCapri.kext kernel extension with a slightly modification.
My Mac Mini is a small beast with 16 GB RAM, 500 GB SSD and a quad core 2.6 Ghz CPU but the Intel HD4000 chip is just not the best option for 4K displays but it worked under Maverick and I knew that.
I tried to see if could restore the 4K resolution but with no luck. It is just not a good idea to play around with the kernel extension in Apple but I certainly learned a few things about the Mac OS X kernel API, caching and file locations. Several people seems to have fixed the problem.
3 solutions exists for me at the moment:
- Revert to Maverick OS X
- Use the Maverick AppleIntelFramebufferCapri.kext in order to patch the running Yosemite on my Mac Mini.
- Apple will this in the future (not likely)
I am not sure that Apple will ever fix this. I do know that Apple is aware of the problem as it has been reported during the Yosemite Beta testing. This really irritates me a lot. Come on Apple, fix this.
Finally fixed this. After the whole patching circus i found a little trick for display more resolution options. Go to System Preferences in Yosemite -> Displays -> Display tab. Hold down option + left mouse click on Scaled. BOOM! Now the 3440 x 1440 resolution could be selected.