All displays go black after turning on the second display

[GroundedCopilot]

Hi Team, 

This is my first time in the forum and I need your help because I am frustrated with the problem I am facing. I have read many forums and tried many tweaks but my issue hasn't been resolved. 

My issue: I have 2 x U2515H displays connected through a daisy chain. My main display is connected through a DP. When I boot up my Hackintosh running Catalina (happened with Mojave) and the main display is turned on a the second is turned off it all boots fine. However after Catalina has boot up and then I try to turn on the second display both displays go black and enter a power saving mode. The only way to get my displays working after this is to connect my displays to my HDMI port. What us also really interesting is when I boot with both displays on, they are mirror images. If I then try to go into the display settings the arrangement tab is missing.

 

I really need my 2 displays to work in extended view mode for productivity.

 

Your help would be greatly appreciated

 

My build is: z390 Aorus Pro WiFi | Sapphire Nitro+ Radeon RX 580 8 GB GDDR5 | i5 9600k Coffee Lake | Samsung Pro 970 M.2 | Dell U2515H

Key Bios settings: CSM - enabled | Internal graphics - disabled | 4G decoding - disabled

[Maf3r0]

Well, you must take a look in some things:

 

1st point: Whatevergreen can perform most required patches to enable video automatically. But to do it, yout must disable and/or remove DSDT patch GFX0->iGPU and all fixes related to audio/video, like: FixDisplay, AddIMEI, FixIntelGfx, AddHDMI, etc and set Inject » ATI and Intel to No (select and then deselect).

Also, remove boot arg: -disablegfxfirmware and kexts like FakePCIID_Intel_HD_Graphics.

 

2nd point: Why disable iGPU? I have dual display set up with both iGPU and dGPU – at same time…and many people says that is the best config to macos – even to a single display. Here, i had set dGPU (PCIe slot) as initial display output, conected trough HDMI to main monitor and iGPU conected trough DVI-d to second monitor.

 

But, to get this working well I need set:

• correct values into DVMT Pre-Allocated, Total Gfx Mem and Aperture Size (have to try each one);

• correct AptioFix driver (test until find more compatible);

• Hackintool patch to enable UHD630 (ig-platform-id can be set instead this).

 

Buuuut… if you want to use only dGPU, just disable iGPU and done – once ur card should be work oob.

 

CSM and 4G decoding no matter Enabled or Disabled. But appears that 4G decoding is required to 4k resolution – I dont know if thats is ur case. Here, I've this Enabled w/o any problem.

 

3rd point: Leave only mandatory kexts to avoid potential conflicts. I'm not an expert, but I think boot arg UIA_exclude must be used just when configuring SSDT-UIAC. So, I think that's can also be removed, or not…I dont know.

 

[GroundedCopilot]

@Maf3r0 thank you for your response. I have had a half win. With your suggestions I have been able to at least run the second display through a HDMI connection. Main display is connected using DP and the second through a HDMI connection. Unfortunately, daisy chaining one display to the second one through a DP still results in a black screen when I turn on the power to the second display. Now to my next task, fixing my iGPU which isn't registering as UHD 630 but instead as an Intel HD Graphics CFL CRB