Desktop Multiple GPUs (WindowServer & Metal errors)

[oliveiro]

Hi community !

Is anybody successful with 10.13.x and multiple GPUs on a desktop hack ?

My main rig (see in signature) HD4600 + GTX550Ti + GTX560 is working perfectly under 10.11.6 and 10.12.6.

Very simple to install, Intel IGPU set to active and primary in bios, inject intel and igplatformid in bootloader (enoch or clover), no nividia injection, since Fermi GPUs are natively supported. Smbios set to iMac14.2 for my Haswell CPU, and to avoid AppleGraphicsDeviceControl devices unloading.

But from 10.13.0 to 10.13.3, system boots fine until login screen where WindowServer crashes with a "no MTLDevice" error (MeTaL device I guess). I could workaround that error by unloading nvidia devices in AppleGraphicsDeviceControl, but that kind of defeats the purpose, since only the IntelHD4600 can then be used.

10.13.4 brings a little improvement, desktop can be reached, all 3 gpus active (AppleDisplay instances appear in IORegistryExplorer for Intel and Nvidias) but only Intel HDMI output shows desktop correctly, both nvidias (HDMI or DVI output) only show a black desktop where the mouse pointer can be moved normally. Displays can be arranged, orientation and resolution can be changed, as if everything was fine, but it is not.

Console shows the following repeated messages :

     WindowServer (Skylight) : Unable to composite display surface due to null compositor.

     WindowServer (CoreDisplay) : [ERROR] - Attempting to get capabilities from capabilities with no devices

Does anybody have an idea on how to avoid or workaround these errors ?

Thanks !

O.

Things I've tried:

• Bios Graphic Devices order changes (breaks everything unless IGPU is primary)
• nvidia injection in bootloader (fails in enoch, disables secondary nvidia GPU outputs in clover)
• Smbios changes and/or AppleDeviceControlPolicy plist edits (simply enables or disables nvidia outputs)
• nvidia official or web drivers (no changes at all, even though webdrivers are properly loaded ; requires nvram emulation with enoch)
• enoch or clover (no difference except clover boots a bit faster - than enoch with nvram - thanks to proper UEFI boot I guess)
• lilu intel and/or nvidia and/or coredisplay graphicsfixups (no visible changes but graphics devices names, and thus enables or disables AGPM)
• use binaries from Sierra 10.12.6 for CoreDisplay and/or Skylight frameworks (never reached desktop)
• NVIDIAeGPUSupport (no changes)