drm/amdkfd: set CP_HQD_PQ_CONTROL.SCOPE to SYSTEM for GFX 12.1

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On GFX 12.1, ring buffers may be mapped with a non-coherently
cached memory type. In that case the queue fetch can observe stale
packets, since the packet producers (CPU or other GPUs) do not keep the
device-side cache coherent.

Set CP_HQD_PQ_CONTROL.SCOPE=3 (SYSTEM) so the queue fetches use
system scope and pick up the latest packets. Apply this to compute queue
MQDs and to MES-managed queues.

Without this, the queue can consume stale packets for long periods,
causing severe slowdowns and, in the worst case, application hangs.

Reviewed-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Signed-off-by: Joseph Greathouse <joseph.greathouse@amd.com>
Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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This commit is contained in:

Mukul Joshi 2026-09-14 18:09:31 -04:00 • committed by Alex Deucher

parent 5119c21145

commit b2adbdf861

2 changed files with 2 additions and 0 deletions

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1

drivers/gpu/drm/amd/amdgpu/mes_v12_1.c

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1

drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v12_1.c

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