I have dual monitors working on a 10.11.6 skylake build using the internal 530 GPU. Since I followed cnrd's guide for my motherboard (
[GUIDE] El Capitan on the GA-Z170X-UD3) I used the MacPro 6,1 SMBIOS. Using this SMBIOS (or the iMac 17,1 or iMac 17,2 SMBIOS) seems to require the AGDPFix.app from
https://www.tonymacx86.com/threads/...-imac-15-or-imac-17-system-definition.183113/.
I have several patches in my Clover config. I found the comments about using IORegistryExplorer confusing so I wanted to lay out how I applied the comments to my situation.
First I followed the changes in post #1 in this thread: inject Intel = Yes, ig-platform-id = 0x19120000, and the 4 ports patch. After doing this, opening IORegistryExplorer (you can download it at developer.apple.com/downloads/more, choose the right additional tools or hardware IO tools for Xcode, may require Xcode first) and typing "display" into the search box will limit the output to a tree showing your video output. You'll see AppleFramebuffer@0, AppleFramebuffer@1, ..@2 and @3 (after applying the patch, and a reboot).
You're trying to figure out what ports you have, and what connector type each port is using. In my case, after rebooting, I had
AppleFrambuffer@0: connector-type 00 02 00 00, port-number 0x7
AppleFrambuffer@1: connector-type 00 04 00 00, port-number 0x5
AppleFrambuffer@2: connector-type 00 04 00 00, port-number 0x6
AppleFrambuffer@3: connector-type 00 04 00 00, port-number 0x7
My understanding is that the 0x19120000 ig-platform-id represents a physical device with 3 display port output ports. My actual hardware is 1 DVI, 1 HDMI, and 1 VGA. I didn't care about VGA, but I wanted the DVI and HDMI ports to have the correct connector type. connector type with 02 is is DVI, connector type with 04 is display link, and 08 is HDMI. So I wanted to establish which port was which, and get the right connector type. To do this, I used the patches earlier in this thread which apply changes to AppleIntelSKLGraphicsFramebuffer.kext via the KextsToPatch section of the Graphics tab in Clover Configurator. Plugging in one monitor at a time and booting, and going into ioreg, I determined that for my system, port 5 was my HDMI port, and port 6 was my DVI port. You can tell because in the tree in ioreg, you'll see a child representing the monitor under the port it's connected to. I ignored port 0x0. I applied the following patches:
<dict>
<key>Comment</key>
<string>10.11-SKL-Port_0x6-DP2DVI</string>
<key>Find</key>
<data>
AgQKAAAEAACHAQAA
</data>
<key>Name</key>
<string>AppleIntelSKLGraphicsFramebuffer</string>
<key>Replace</key>
<data>
AgQKAAACAACHAQAA
</data>
</dict>
<dict>
<key>Comment</key>
<string>10.11-SKL-Port_0x5-DP2HDMI</string>
<key>Find</key>
<data>
AQUJAAAEAACHAQAA
</data>
<key>Name</key>
<string>AppleIntelSKLGraphicsFramebuffer</string>
<key>Replace</key>
<data>
AQUJAAAIAACHAQAA
</data>
</dict>
Note that these are the values you see if you open config.plist in a text editor; if you open Clover Configurator and open your config, you'll see long alpha-numeric strings. Note that the replace bucket will have a prominent "00020000", "00040000", "00080000" or something else in the middle, so you can just change those to the right connector type for your port for each port you want to configure.
Finally I applied the AGDPFix.app, and was able to boot with one monitor on and one off, and turn on the second monitor at the desktop, and have it come on. Which monitor you start with seems to be specific to your setup, try it one way then the other to figure out which works best. In my case, on the first try, my DVI monitor's "on" light sort of rapidly pulsed but the screen didn't come on. I tried it with the other monitor first, and the second one came on at the desktop perfect.
