[PATCH v2] drm/amdkfd: Initialize only amdkfd's assigned pipelines

[Oded Gabbay]

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 at amd.com>
Cc: stable at vger.kernel.org
Tested-by: Michel Dänzer <michel.daenzer at amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c     | 4 ++--
 drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h     | 1 +
 drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager_cik.c | 2 +-
 3 files changed, 4 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 36b95e1..2fbadd5 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -62,9 +62,9 @@ enum KFD_MQD_TYPE get_mqd_type_from_queue_type(enum kfd_queue_type type)
 	return KFD_MQD_TYPE_CP;
 }
 
-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;
 }
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
index d64f86c..386bd7d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
@@ -163,6 +163,7 @@ void program_sh_mem_settings(struct device_queue_manager *dqm,
 					struct qcm_process_device *qpd);
 int init_pipelines(struct device_queue_manager *dqm,
 		unsigned int pipes_num, unsigned int first_pipe);
+unsigned int get_first_pipe(struct device_queue_manager *dqm);
 
 extern inline unsigned int get_sh_mem_bases_32(struct kfd_process_device *pdd)
 {
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager_cik.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager_cik.c
index 6b07246..5469efe 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager_cik.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager_cik.c
@@ -131,5 +131,5 @@ static int register_process_cik(struct device_queue_manager *dqm,
 
 static int initialize_cpsch_cik(struct device_queue_manager *dqm)
 {
-	return init_pipelines(dqm, get_pipes_num(dqm), 0);
+	return init_pipelines(dqm, get_pipes_num(dqm), get_first_pipe(dqm));
 }
-- 
1.9.1