Spoofing GPU device-id (B450m, AMD FirePro)

[rich4653 0]

Had to jump through a few hoops to spoof my GPU device-id. I thought sharing might help somebody else out because I couldn't find this particular pattern anywhere...

 

First I had to create an SSDT to (I assume) define GFX0 as shown:

DefinitionBlock ("", "SSDT", 2, "DRTNIA", "AMDGPU", 0x00001000)
{
    External (_SB_.PCI0.GPP8, DeviceObj)

    Scope (\_SB.PCI0.GPP8)
    {
        Device (GFX0)
        {
            Name (_ADR, Zero)  // _ADR: Address
		}
	}
}

Wasn't able to successfully define the device-id in the SSDT, but once I added GFX0 in the SSDT, I was able to set it via DeviceProperties. Along the lines of:

DeviceProperties -> Add -> PciRoot(0x0)/Pci(0x2,0x0) -> device-id

 

where PciRoot for GFX0 can be found with gfxutil, and device-id will be specific to your GPU 

 

 

My system:

MSI B450 Mortar

Ryzen 5 3600

AMD FirePro W5100

 

Opencore 0.6.2

Catalina 10.15.7