There is a race condition which leads to dpm video power
profile switch (disable and enable) during active video
decode on multi-instance VCN hardware.
This patch aims to fix/skip step 3 in the below sequence:
- inst_1 power_on
- inst_0(idle) power_off
- inst_0(idle) video_power_profile OFF (step 3)
- inst_1 video_power_profile ON during next begin_use
Add flags to track ON/OFF vcn instances and check if all
instances are off before disabling video power profile.
v2: (David Wu)
- pg_lock is per instance it doesn't help solve the issue.
- protect flags also with global workload_profile_mutex.
Signed-off-by: Sathishkumar S <sathishkumar.sundarar...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 24 +++++++++++++++---------
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h | 4 ++++
2 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
index 9a76e11d1c18..b677b287dd49 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
@@ -447,7 +447,14 @@ static void amdgpu_vcn_idle_work_handler(struct
work_struct *work)
vcn_inst->set_pg_state(vcn_inst, AMD_PG_STATE_GATE);
mutex_unlock(&vcn_inst->vcn_pg_lock);
mutex_lock(&adev->vcn.workload_profile_mutex);
- if (adev->vcn.workload_profile_active) {
+ if (!adev->vcn.workload_profile_active &&
+ !(adev->vcn.flags &
AMDGPU_VCN_FLAG_VINST_MASK(adev->vcn.num_vcn_inst))) {
+ /* video profile is active , we are holding global
workload_profile_mutex.
+ * it is safe to check if flags are 0 here and be
assured that all instances
+ * are off, since no other begin_use paths can be
holding this lock now.
+ * so off video_power_profile and update
workload_profile_active = false
+ * since all vcn instances are inactive here.
+ */
r = amdgpu_dpm_switch_power_profile(adev,
PP_SMC_POWER_PROFILE_VIDEO,
false);
if (r)
@@ -470,24 +477,23 @@ void amdgpu_vcn_ring_begin_use(struct amdgpu_ring *ring)
cancel_delayed_work_sync(&vcn_inst->idle_work);
- /* We can safely return early here because we've cancelled the
- * the delayed work so there is no one else to set it to false
- * and we don't care if someone else sets it to true.
- */
- if (adev->vcn.workload_profile_active)
- goto pg_lock;
-
mutex_lock(&adev->vcn.workload_profile_mutex);
if (!adev->vcn.workload_profile_active) {
+ /* If inactive proceed to ON video_power_profile and update
workload_profile_active */
r = amdgpu_dpm_switch_power_profile(adev,
PP_SMC_POWER_PROFILE_VIDEO,
true);
if (r)
dev_warn(adev->dev, "(%d) failed to switch to video
power profile mode\n", r);
adev->vcn.workload_profile_active = true;
}
+ /* Holding global workload_profile_mutex, so none of the idle handlers
can access flags.
+ * and cannot OFF video_power_profile at this point. Can safely update
vcn.flags to
+ * indicate active vcn instances, which is visible to any idle handlers
who later grab
+ * this lock and check flags for any active vcn instances.
+ */
+ adev->vcn.flags |= AMDGPU_VCN_FLAG_VINST_ON(vcn_inst->inst);
mutex_unlock(&adev->vcn.workload_profile_mutex);
-pg_lock:
mutex_lock(&vcn_inst->vcn_pg_lock);
vcn_inst->set_pg_state(vcn_inst, AMD_PG_STATE_UNGATE);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
index b3fb1d0e43fc..a876a182ff88 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
@@ -366,6 +366,10 @@ struct amdgpu_vcn {
struct mutex workload_profile_mutex;
u32 reg_count;
const struct amdgpu_hwip_reg_entry *reg_list;
+#define AMDGPU_VCN_FLAG_VINST_MASK(n) (BIT(n+1) - 1)
+#define AMDGPU_VCN_FLAG_VINST_ON(n) (BIT(n))
+#define AMDGPU_VCN_FLAG_VINST_OFF(n) (~BIT(n))
+ u32 flags;
};
struct amdgpu_fw_shared_rb_ptrs_struct {
--
2.48.1
