This is a backport of patch original made for kernel v4.0, with commit id
1365aa6266fad0669487240af3f098593796172c
This patch fixes a bug in the initialization of the pipelines. The
init_pipelines() function was called with a constant value of 0 in the
first_pipe argument. This is an error because amdkfd doesn't handle pipe 0.
The correct way is to pass the value that get_first_pipe() returns as the
argument for first_pipe.
This bug appeared in 3.19 (first version with amdkfd) and it causes around 15%
drop in CPU performance of Kaveri (A10-7850).
v2: Don't set get_first_pipe() as inline because it calls BUG_ON()
Signed-off-by: Oded Gabbay <oded.gabbay@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Michel Dänzer <michel.daenzer@xxxxxxx>
---
drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 0fd5927..c80a8a3 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -56,9 +56,9 @@ static inline unsigned int get_pipes_num(struct device_queue_manager *dqm)
return dqm->dev->shared_resources.compute_pipe_count;
}
-static inline unsigned int get_first_pipe(struct device_queue_manager *dqm)
+unsigned int get_first_pipe(struct device_queue_manager *dqm)
{
- BUG_ON(!dqm);
+ BUG_ON(!dqm || !dqm->dev);
return dqm->dev->shared_resources.first_compute_pipe;
}
@@ -693,7 +693,7 @@ static int initialize_cpsch(struct device_queue_manager *dqm)
INIT_LIST_HEAD(&dqm->queues);
dqm->queue_count = dqm->processes_count = 0;
dqm->active_runlist = false;
- retval = init_pipelines(dqm, get_pipes_num(dqm), 0);
+ retval = init_pipelines(dqm, get_pipes_num(dqm), get_first_pipe(dqm));
if (retval != 0)
goto fail_init_pipelines;
--
1.9.1
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