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[regression][bisected] AMDGPU rejects Tahiti GPUs in 5.16

Brief summary of the problem:

AMDGPU rejects Tahiti devices in amdgpu_pci_probe with the log message Unsupported asic. Remove me when IP discovery init is in place. This happens because CHIP_TAHITI of the amd_asic_type enum (defined in include/drm/amd_asic_type.h) is 0 and the check in amdgpu_pci_probe assumes that a driver_data field containing 0 means that the device is unsupported.

The bug could probably be resolved by either setting CHIP_TAHITI = 1 in amd_asic_type.h or by using a driver_data field of -1 to flag unsupported devices (see the commit below).

This faulty check was added in eb4fd29afd4aa1c98d882800ceeee7d1f5262803.

Hardware description:

  • CPU: Intel Core i5-3570K
  • GPU: AMD Tahiti XT (R9 280X) [1002:6798]

System information:

  • Distro name and Version: Arch Linux
  • Kernel version: Linux 5.16.0-arch1-1 #1 (closed) SMP PREEMPT Mon, 10 Jan 2022 20:11:47 +0000 x86_64

How to reproduce the issue:

  • Boot with an AMD Tahiti GPU and kernel cmdline radeon.si_support=0 amdgpu.si_support=1