Dell Precision M6800: HDMI dummy = K4100M on internal display ?

[Hervé]

Possibly. You would have to disable Optimus, boot with an external screen connected and take an IOReg that we can then have a look at in order to identify the built-in LCD if it registers against a port. In case you need to get in remotely via VNC, 1st ensure you enable Screen Sharing via Sharing PrefPane. We can have a look at the guy's EFI in order to inject the associated NVCAP in your config.

[draskostar]

Please find enclosed ioreg file while Optimus disabled, with Nvidia only. I used my TV for external screen, connected through HDMI.

 

FYI. I was also trying with smbios 11.3 in the past but that didn't help either.   

 

Thanks!

MacBook Pro_optimus_disabled.ioreg

[Hervé]

Ok, no display registers other than your TV screen on port #4 (Display-D@3). NVCAP shows the following value:

050000000000ffffffff00000000000e00000000

 

There are a few things you can try regarding this EFI string and your Clover config:

1. inject it as is. It goes into the Properties [Hex] field in Clover Configurator. I'd save it into a separate config that you call from Clover main menu. You can then post a new IOReg after rebooting with the EFI string applied. I don't recommend this because the string contains an entire set of nVidia properties and they don't really apply to your laptop.
2. you inject the NVCAP it contains after decoding the string. It's the NVCAP that defines the dGPU output ports.

 

If you use old 32bit tools such as EFIStudio, you can decode the EFI string and you'll see it's as follows:

nVidia_properties.plist.zip

EFIStudio.zip

 

Basically, it injects the following properties:

 

where you can clearly see an injected NVCAP value of:

0500000000000100060000000000000F00000000 

 

Also to be noticed and noted:

• built-in LCD set to boot display
• built-in LCD EDID injection

 

[draskostar]

I am using opencore. Does this matter? I can’t open efistudio. It says that needs to update.

 

Anyway I added nvidia path in device proprieties with injected NVCAP but after reboot pc stuck at Apple logo (during loading). I used manual from dortania. 
 

During my testing I was always connected to my tv with optimus disabled.

 

Should I eject also EDID of the internal screen? In this case I must enable optimus back again to get EDID of internal screen?

[Hervé]

'thought you were using Clover but makes no difference.

 

macOS will show the built-in LCD's EDID in IOReg if the screen is available. Of course you may compare what's shown in IOReg under macOS with the info that various tools (for Windows) would show.