E7440 garbled screen with increased DVMT patch

[rgwoehr]

I've got my E7440 running 10.13.5 pretty much flawlessly, but the max resolution of the HDMI and miniDP ports is 1080P, and I'm trying to get it to output 4K like it can do in Windows. I've tried using clover patches and WhateverGreen to increase the DVMT, but it seems anything over the default 32MB causes the screen to be severely distorted. When I increased it to 128MB using the WhateverGreen method of increasing DVMT, it did output 4K through the HDMI port but it was so glitchy that it was unusable. Is there something I'm missing? Or is this just a limitation of the HD4400 in OS X?

 

I should mention I didn't use the bootpack for this machine. The only thing I used from it was the DSDT because I was having issues patching it myself. I'm only using Lilu+WEG+9mb cursor patch in config.plist for graphics. I saw that the boot pack uses FakePCIID_Intel_HD_Graphics.kext but when I installed that, I saw no difference.

[rgwoehr]

I think I've figured it out. I was under the impression you could set the DVMT higher than the default bios setting using framebuffer patches or IntelDVMTFixup/Whatevergreen. I used the EFI shell method for increasing the DVMT to set it to 128mb and applied the framebuffer patches, and that seems to have stopped the flickering and distortion I was getting before. There are still some occasional issues, but I'm going to keep tweaking the framebuffer patch until I find something that works.