[PATCH V2 1/2] drm/amdgpu/gfx: fix ref counting for ring based profile handling

[Alex Deucher]

We need to make sure the workload profile ref counts are
balanced.  This isn't currently the case because we can
increment the count on submissions, but the decrement may
be delayed as work comes in.  Track when we enable the
workload profile so the references are balanced.

v2: switch to a mutex and active flag

Fixes: 8fdb3958e396 ("drm/amdgpu/gfx: add ring helpers for setting workload profile")
Cc: Yang Wang <kevinyang.wang at amd.com>
Cc: Kenneth Feng <kenneth.feng at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 30 ++++++++++++++++---------
 drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h |  2 ++
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
index 984e6ff6e4632..099329d15b9ff 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
@@ -2160,11 +2160,16 @@ void amdgpu_gfx_profile_idle_work_handler(struct work_struct *work)
 	for (i = 0; i < (AMDGPU_MAX_COMPUTE_RINGS * AMDGPU_MAX_GC_INSTANCES); ++i)
 		fences += amdgpu_fence_count_emitted(&adev->gfx.compute_ring[i]);
 	if (!fences && !atomic_read(&adev->gfx.total_submission_cnt)) {
-		r = amdgpu_dpm_switch_power_profile(adev, profile, false);
-		if (r)
-			dev_warn(adev->dev, "(%d) failed to disable %s power profile mode\n", r,
-				 profile == PP_SMC_POWER_PROFILE_FULLSCREEN3D ?
-				 "fullscreen 3D" : "compute");
+		mutex_lock(&adev->gfx.workload_profile_mutex);
+		if (adev->gfx.workload_profile_active) {
+			r = amdgpu_dpm_switch_power_profile(adev, profile, false);
+			if (r)
+				dev_warn(adev->dev, "(%d) failed to disable %s power profile mode\n", r,
+					 profile == PP_SMC_POWER_PROFILE_FULLSCREEN3D ?
+					 "fullscreen 3D" : "compute");
+			adev->gfx.workload_profile_active = false;
+		}
+		mutex_unlock(&adev->gfx.workload_profile_mutex);
 	} else {
 		schedule_delayed_work(&adev->gfx.idle_work, GFX_PROFILE_IDLE_TIMEOUT);
 	}
@@ -2184,11 +2189,16 @@ void amdgpu_gfx_profile_ring_begin_use(struct amdgpu_ring *ring)
 	atomic_inc(&adev->gfx.total_submission_cnt);
 
 	if (!cancel_delayed_work_sync(&adev->gfx.idle_work)) {
-		r = amdgpu_dpm_switch_power_profile(adev, profile, true);
-		if (r)
-			dev_warn(adev->dev, "(%d) failed to disable %s power profile mode\n", r,
-				 profile == PP_SMC_POWER_PROFILE_FULLSCREEN3D ?
-				 "fullscreen 3D" : "compute");
+		mutex_lock(&adev->gfx.workload_profile_mutex);
+		if (!adev->gfx.workload_profile_active) {
+			r = amdgpu_dpm_switch_power_profile(adev, profile, true);
+			if (r)
+				dev_warn(adev->dev, "(%d) failed to disable %s power profile mode\n", r,
+					 profile == PP_SMC_POWER_PROFILE_FULLSCREEN3D ?
+					 "fullscreen 3D" : "compute");
+			adev->gfx.workload_profile_active = true;
+		}
+		mutex_unlock(&adev->gfx.workload_profile_mutex);
 	}
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h
index ddf4533614bac..75af4f25a133b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h
@@ -483,6 +483,8 @@ struct amdgpu_gfx {
 
 	atomic_t			total_submission_cnt;
 	struct delayed_work		idle_work;
+	bool				workload_profile_active;
+	struct mutex                    workload_profile_mutex;
 };
 
 struct amdgpu_gfx_ras_reg_entry {
-- 
2.48.1