drm/amdgpu: fix empty fence backup and replay intervals

amdgpu_ring_set_fence_errors_and_reemit() and
amdgpu_ring_backup_unprocessed_commands() masked last_seq and sync_seq to
fence-array indices before the loop, then walked a do/while until the two
indices met. When hardware completed every command before the driver
signalled the fences, last_seq == sync_seq, but the masked-index do/while
could not tell that empty interval from a full table and walked the whole
fence array, backing up and replaying already-completed commands.

Read the raw sequence numbers, return early through amdgpu_fence_process()
when they are equal, and mask only at the array index. Guard the
force-completion against a NULL guilty_fence so a non-guilty backup does
not dereference it.

Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 78fbe156637a11456fcd29615a56e098ec8a6990)

0 files changed, 0 insertions, 0 deletions