drm/amdkfd: Initialize only amdkfd's assigned pipelines

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@amd.com>
Cc: stable@vger.kernel.org
Tested-by: Michel Dänzer <michel.daenzer@amd.com>

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 b3589d0e39b9..1b58f331afee 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 d64f86cda34f..386bd7df7c30 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 6b072466e2a6..5469efe0523e 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));
 }