Dell Optiplex 3050 microFF: help with dual display at startup

[naquiyankee]

Hi there! I think I could use some help here. 
I just installed macOS Monterrey on my Dell Optiplex 3050 microFF. I am using dual monitors through DP and HDMI ports, however, at startup, the monitor hooked up to DP works, the HDMI doesn't, I need to unplug the HDMI and plug it back to make it work.
I am just a beginner and followed the dortania guide. I was trying to patch the connectors, but to be honest, I am a little confused and I don't understand it. I would like to be able to use both monitors without unpluging and pluging back. I attach a screenshot of my config.plist and IOREgistry explorer.

 

 

 

 

[Jake Lo]

Which port is HDMI?

When you find out, patch it for HDMI. Currently it shows both being DP ports

[Hervé]

You use SKL framebuffer atout 0x19120000 which defines the following properties:

ID: 19120000, STOLEN: 34 MB, FBMEM: 21 MB, VRAM: 1536 MB, Flags: 0x0000110F
TOTAL STOLEN: 56 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 124 MB, MAX OVERALL: 125 MB (131608576 bytes)
Model name: Intel HD Graphics SKL CRB
Camellia: CamelliaDisabled (0), Freq: 1388 Hz, FreqMax: 1388 Hz
Mobile: 1, PipeCount: 3, PortCount: 3, FBMemoryCount: 3
[255] busId: 0x00, pipe: 0, type: 0x00000001, flags: 0x00000020 - ConnectorDummy
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x00000187 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x00000187 - ConnectorDP
FF000000 01000000 20000000
01050900 00040000 87010000
02040A00 00040000 87010000

 

As suggested by Jake, once you've identified in IOReg which connector your HDMI output attaches to (in all likelihood con1, i.e.AppleIntelFramebuffer@1 but it may be con2, i.e AppleIntelFramebuffer@2), patch its type by adding the following lines to your injected iGPU properties set:

framebuffer-conX-enable    1           NUMBER
framebuffer-conX-type      00080000    DATA

where X is 1 or 2.

 

HDMI output can also be a little difficult at times on Skylake HD5x0. Make sure to add Whatevergreen boot arg igfxonln=1 in your bootloader config.

 

See the Whatevergren documentation and user manual.