<< Solved >> GPU SSDT not working

[darthtaoist]

I don't have it anymore, I deleted it.
Because I finally could get it to work by "SSDT" method, which is better.

I explained how I did it on my first post.

I just wanted to thank you for sticking to this and uploading your SSDT. Your guide is the one that did it for me, I tried a couple others and got the name to update, but the graphics was still low quality. Even using https://dortania.github.io/Getting-Started-With-ACPI/Universal/spoof.html didn't work. Only your SSDT worked.

 

[moremac]

I just wanted to thank you for sticking to this and uploading your SSDT. Your guide is the one that did it for me, I tried a couple others and got the name to update, but the graphics was still low quality. Even using https://dortania.github.io/Getting-Started-With-ACPI/Universal/spoof.html didn't work. Only your SSDT worked.

You're welcome!
I'm glad it worked for you too.

 

[Sathiskoppadu]

Hello!
I sucessfully installed Big Sur on a x79 motherboard with OC.
But I still have a problem, I can't get the RX550 4GB graphics to work.

And I found a SSDT showing how to fake ID a RX550. (check "SSDT-DELL-5820-X299-RX550.aml")
I edited the part of GPU ACPI path to mine but it still didn't work.

Maybe I'm doing something wrong, or the SSDT might need an update or a different code, "buffer" numbers might be wrong.
I really don't know what else to do.
I've never done this GPU SSDT thing before.
Somebody please help me.

SOLVED

View attachment 518865

I attached a sample "SSDT-RX550.dsl" to help anyone who needs it.

You just need to add your GPU ACPI path on:
External (_SB_.PCI0.PEG0.PEGP, DeviceObj)
Scope (_SB.PCI0.PEG0.PEGP)
The GPU path can be shorter sometimes (mine didn't have "PEGP", so I removed it)

And also add your GPU "AAPL,slot-name" path.
Compile it, and done.

My custom sample doesn't have support for the "HDAU", I didn't need it.
But if you need it, you can copy the code from "SSDT-DELL-5820-X299-RX550.aml"

How I did:
Besides my GPU info, it was just a change of codes that solved it.

I removed the "buffer" numbers/letters copied from "SSDT-DELL-5820-X299-RX550.aml"
And left them blank "Buffer ()" because when you compile later, these numbers/letters will be added automatic.

And I also removed the "External (DTGP)" from the header
And put this at the end:

    Method (DTGP, 5, NotSerialized)
    {
        If (LEqual (Arg0, ToUUID ("a0b5b7c6-1318-441c-b0c9-fe695eaf949b")))
        {
            If (LEqual (Arg1, One))
            {
                If (LEqual (Arg2, Zero))
                {
                    Store (Buffer (One)
                        {
                             0x03                                     
                        }, Arg4)
                    Return (One)
                }

                If (LEqual (Arg2, One))
                {
                    Return (One)
                }
            }
        }

        Store (Buffer (One)
            {
                 0x00                                     
            }, Arg4)
        Return (Zero)
    }
}

I copied from here: https://github.com/acidanthera/WhateverGreen/blob/master/Manual/Sample.dsl