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eGPU support will depend on if they have a way to work around the need for a PCIe I/O BAR. Many GPUs require that to initialize and as far as I know no ARM cpu
by simcop2387 6y ago
eGPU support will depend on if they have a way to work around the need for a PCIe I/O BAR. Many GPUs require that to initialize and as far as I know no ARM cpus support it since it's a legacy-ish x86 thing. It'll be the same problem that prevents gpu use on raspberry pi 4s still. I bet you can make a controller that'll provide a mapping for that to allow it but that'll mean needing a new enclosure (probably not a huge deal) and new silicon and drivers.
- dwaite 6y agoI don't quite get how Apple could claim to be Thunderbolt-compatible with this sort of limitation in hardware, though.
- djxfade 6y agoIt's not a limitation in hardware. It's a legacy feature of the x86 that isn't supported on ARM. This could be solved by the GPU engineers by removing the legacy compatibility. "Nobody" boots a modern PC from BIOS anymore
- SXX 6y agoAMD GPUs work just fine with POWER8 hardware so this is certainly solved.
- marcan_42 6y agoAMD GPUs do not require I/O BARs, and highly doubt Nvidia ones do either. The VBIOS will probably assume it can use it, but most modern cards can be initialized without actually running the VBIOS (because people use them on headless servers, for virtualization, and things like that). The I/O BAR is only required for legacy VGA compatibility, you can ignore it.