[Solved] R9 280X only works on displayport in High Sierra

[Michael-Irvine]

Hi there

I have a problem that I have been trying to solve for a while now and I can't seem to work it out. I currently have connected 2 monitors one through displayport and another through an HDMI to DVI adapter.

These monitors are connected to my Gigabyte R9 280X and only seem to display something if connected to a display port whether both monitors are connected or not. If a monitor is connected to the DVI or HDMI port then everything will work up until the login screen where the screen stays on but is black. If a monitor is connected to the display port then it will work perfectly fine.

Another thing to note is that the monitor that is black is detected in system preferences and shows up there but is simply black.

I have tried radeondeinit as well as lilu and whatevergreen but that has not solved my problem.

I am running High Sierra and have tried to make sense of the frame buffers but don't understand it and if that is what is going to fix this then could you please explain it in a little more detail please?

Thanks and I really appreciate any guidance for fixing this issue.

 

[gromek82]

Hello,

I've got similar problem. Just upgraded to High Sierra and found out my GTX660 doesn't work so I replaced it with MSI R9 280X (2 mDP, 1 HDMI and 1 DVI). I've managed to boot up fine and have 2 monitors displaying fine while they are connected to mDP only. The problem I've got is when I want to add 3 monitor using HDMI it gets detected but it stays black. Also I noticed that one of two working monitors is (plugged to mDP via connector mDP to HDMI) is using YPbPr colour format and it's looking pretty bad.
When I change the input colour to RGB screen changes to Green and pink.

I'm injecting lates Lilu.kext and WhateverGreen.kext via Clover. I tried with ATI injected and without it and with FakeID but it doesn't change anything. FB I am using is Hamachi.

Am I missing something ? I read some statements that iGPU might be required for 3rd monitor to work but I don't have a connector for integrated GFX as this is Dell Precision T3600.

Any help is greatly appreciated.

 

[Michael-Irvine]

So are you getting any output from your DVI or HDMI ports on their own from the R9 280X?

I have attempted to get any picutre from these and it just remains black but is detected. I have also attempted to get the IGPU working alongside it but all I get when the login screen should appear is random green lines.

I forgot to mention I am running SMBIOS 13,2 if that is at all relevant.

Gromek82 do you think you could describe what you did to get the frame buffer going please it would be greatly appreciated.

 

[gromek82]

@Michael-Irvine
Same thing. I can only get dual display by using 2 x mDP. When I add HDMI it gets detected but it's black. If I add DVI it's all green. I haven't played with custom FBs since this card should be supported out of the box.

Can anyone confirm please if custom FB can fix display so I can use 3 monitors ?

 

[Michael-Irvine]

@gromek82
I managed to get this going by editing the frame buffer. As far as I am aware the graphics card is now setup as it should be to work from all outputs. I followed the guide here which seemed daunting at first but I found was actually very easy to follow.

I can step you through it if you like to help you better understand what is going on and how I actually managed to get it working.

If you are happy to just follow that guide then for reference I edited the "Namako" buffer from the AMD7000Controller.kext (Which I found out from here is the kext related to the R9 280X) to suit my needs and it just worked. Namako was simply the first frame buffer to edit in that list that had 4 ports like the R9 280X.

 

[gromek82]

@Michael-Irvine
It doesn't work for me unfortunately. I worked out my numbers to be:
12040501
22050402
11020104
10000306
So exactly the same as in a guide. I amended config.plist added inject ATI and Deinit and I cannot get 3 monitors working or even get anything from HDMI. Would you mind sharing you config.plist ?

 

[Michael-Irvine]

My edited Namako frame buffer looked like this:

Namako (4) @ 0xebc00
LVDS, LVDS, DP, DP
000400000403000000010400000000001204050100000000
000400000403000000010100000000002205040200000000
000800000402000000010200000000001102010400000000
000200001402000000010300000000001000030600000000

Once you manage to make that then all you have to do is set the frame buffer to edit as Namako and inject ATI, Intel and RadeonDeInit as seen as the first image attached.

Then you need to go to Kernel and Kext patches and as the R9 280X card is related to the AMD7000controller set the name to AMD7000Controller, for Find [HEX] put in the old Namako hex value as the entire thing e.g

020000000001000000010151000000002205020200000000
020000000001000000010261010000001204010100000000
000400000403000000010343000000001102030300000000
000400000403000000010433000000002103040400000000

then you need to put your edited hex (The edited Namako frame buffer at the start of this reply) in the Replace [Hex] one. It should then look like the second image attached in the reply.

If even then that still doesn't work then you can try to use my config.plist but I don't know for sure if that will work.

If after all of that doesn't work then let me know and I will try to help you out with possibly trying a different frame buffer.

 

[Michael-Irvine]

@gromek82 I am not sure if you got this to work or not and I am not sure how similar your setup was to mine but when I was having issues I was using legacy bios. I have now updated my motherboard bios to uefi and reinstalled high sierra to find that everything works without needing modification as I had done previously.

So if you are not running uefi, and are planning on installing macOS I strongly recommend updating to uefi first and it will likely save a lot of hassle later.

 

[kershner920]

Fresh Vanilla install of Mojave 10.14.6

I struggled with this for hours, same issue as OP, wanted 3 monitors, however, only the mini display ports would work. The minute I added the 3rd monitor via HDMI or DVI it would be detected yet have a black screen and the system would then become unstable. I tried messing with Framebuffers multiple different config.plst edits etc. I also tried a combination of internal graphics and dedicated (unstable). Checked my bios settings and found a way to completely disable legacy bios. Once disabled the OS booted and everything worked OOB. All displays work without issue.