drm/amdgpu: recompute the dw estimate after allocating a new VM update job

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amdgpu_vm_sdma_update() keeps the number of free dwords of the current
job in a local variable. When the job runs out of room it is committed
and a new one is allocated, but that local variable is not refreshed and
still describes the job which was just submitted.

The stale value is then used to decide how many PTEs fit into the new
job. If it happens to be copy_pte_num_dw + 7, or one more than that, the
result is zero. copy_pte() encodes the transfer size as count * 8 - 1,
so a count of zero asks the engine for a 1GB copy starting inside the IB
pool. That runs off the end of the pool, faults on the first unmapped
GART page above it and hangs the ring.

Re-initialize the estimate from the newly allocated job, which is empty
and therefore has its full budget available.

Cc: stable@vger.kernel.org
Signed-off-by: YuBiao Wang <YuBiao.Wang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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YuBiao Wang 2026-07-29 17:53:57 +08:00 • committed by Alex Deucher

parent 1c287e517d

commit a74c7832b1

1 changed files with 5 additions and 0 deletions

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

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