> On 24 Jul 2024, at 10:01 PM, Lukas Wunner <lukas@xxxxxxxxx> wrote: > > On Wed, Jul 24, 2024 at 04:26:58PM +0000, Aditya Garg wrote: >>>> On 24 Jul 2024, at 9:31 PM, Lukas Wunner <lukas@xxxxxxxxx> wrote: >>> I note that on x86, the efistub walks over all PCI devices in the system >>> (see setup_efi_pci() in drivers/firmware/efi/libstub/x86-stub.c) and >>> retrieves the Device ID and Vendor ID. We could additionally retrieve >>> the Class Code and count the number of GPUs in the system by checking >>> whether the Class Code matches PCI_BASE_CLASS_DISPLAY. If there's >>> at least 2 GPUs in the system, invoke apple_set_os. >> >> This also looks like a good idea, but I'm not well aware of the pci >> quirks in the Linux kernel. So, would consider it a bug report for >> the maintainers to fix. > > This is not a PCI quirk in the kernel. The efistub is a separate > program. I'm saying that the efistub already walks over all PCI devices, > it would be trivial to hook into this to count GPUs, recognize the T2 > device or do something else entirely. > I'll leave this to Ard. I'm really confused in choosing the best possible option here. > Thanks, > > Lukas
