Dell optiplex 3040 micro: no multiple displays in BigSur (OpenCore 0.6.3)

[tanya]

Halo,

 

I did a  clean reinstall of  my  Dell optiplex 3040 micro. It use to have it installed with Catalina and Clover, i want to have Big Sur with OpenCore 0.63.

The install succeeded but only  one of the two screens are working .  The HDMI-port  OR  the displayport but not both.  It use to work with Catalina and Clover. 

What do I wrong?  and how can I fix it? .

 

Dell optiplex 3040

proc.    i3 6100T  (skylake) 

mem:   8 Gb ddr3

graph:   intel HD 530

ether:   realtek 8168

wifi:     intel AC8260

 

 

 

tanya’s macmini.ioreg EFI_3040_1screen_only.zip

[Hervé]

You need to:

1. inject additional properties for the desired output ports (i don't think you need to inject device-id 1B19 by the way)
2. change SMBIOS from Mac mini8,1 (a Coffee Lake model) to iMac 17,1 (a Skylake model).
3. add boot arg agdpmod=pikera to bypass the native graphics output restrictions that apply to the selected (SMBIOS) Mac model

Refer to the link I posted here. You'll then have everything.

[tanya]

I changed  1B19. into. 1219.

change to iMac and tried: 

 

 

But still  no DispPort and HDMI at the same time.

 

[Jake Lo]

try settings I had posted it here

Use iMac17,1

 

[Hervé]

@tanya, you did not inject the properties I recommended. In addition, you've entered a totally invalid property "layout-id" which you should remove.

 

Make sure you inject the following properties:

AAPL,ig-platform-id          00001219    DATA
framebuffer-patch-enable     01000000    DATA
framebuffer-fbmem            00009000    DATA
framebuffer-stolenmem        00003001    DATA
framebuffer-pipecount        3           NUMBER
framebuffer-portcount        4           NUMBER
framebuffer-memorycount      3           NUMBER
framebuffer-con1-enable      01000000    DATA
framebuffer-con1-alldata     01050900000800008701000002040A00000400008701000003060A000004000087010000   DATA
hda-gfx                      onboard-1   STRING

 

and add the following boot arg to your NVRAM section, it's mandatory:

agdpmod=pikera

 

Of course, you may also experiment with the ig-platform-id value JakeLo gave in his post.

[tanya]

Hello

 

tried the above and some other things,   (  ig-platform-id, pikera &  vit9696 boot arg,  multiple framebuffer-con-enable )  but no go...   Both  HDMI and DP  ports are working but  NOT at the same time. 

I guess I had to  downgrade to  Catalina/Clover for dual monitor support:  Tons of people with REAL Macmini's also have problems with Dual monitor setup under Big Sur, especially Big Sur beta and Big Sur 11.0.1   .  I guess it's a Big Sur 11.0.1 thing.   See 120+ complaints on  "macOS Big Sur - Multiple Display "… | Apple Developer Forums "  "https://developer.apple.com/forums/thread/651131"   

 

My  Latitude 3400, although,  CAN drive two monitors &  laptop screen with Big Sur ( with minor issue:  must pull out and plug in HDMI cable to get it working) 

[Bronxteck]

you can try adding igfxonln=1 weg flag

[tanya]

Finally succeeded!   Just before giving up on it..  

 

the settings  recommended by Herve but with macmini8,1. (although it is not SkyLake ) did the trick. 

I'm very happy

 

 

 

I'll post my  EFI. and IOreg

 

 

tanya’s Macmini8.ioreg.zip EFI_opt3040micro_bigSur_dualDisplay.zip

[tanya]

With both DP and HDMI plugged in, I  power on.  At first only the DP screen shows the Dell logo,  OC boot menu and apple "-v text" .

When the apple logo appears still a total black (no signal) HDMI screen.  When the Mac login screen appears still a black HDMI screen, but after 6 or 7 second the HDMI screen comes up and stays.   it survives sleep-mode and screen-save mode!   No issues here.