[PATCH v3] drm/amdgpu/vcn: Fix video_profile switch race condition
Sathishkumar S
sathishkumar.sundararaju at amd.com
Thu Aug 14 11:52:53 UTC 2025
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:
Pg_lock is per instance it doesn't help solve the issue. (David Wu)
Use existing global workload_profile_mutex. (Alex)
v3:
Use per instance dpg_lock to protect dpg state changes which
need to be protected agianst concurrent use among users of
one particular instance only, global worload_profile_mutex
need not be used to safe gaurd this and drop pg_lock.
Fixes: 3b669df92c85 ("drm/amdgpu/vcn: adjust workload profile handling")
Signed-off-by: Sathishkumar S <sathishkumar.sundararaju at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 37 +++++++++++--------------
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h | 6 +++-
drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c | 14 ++--------
3 files changed, 23 insertions(+), 34 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
index 9a76e11d1c18..fc61d8875502 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
@@ -134,7 +134,7 @@ int amdgpu_vcn_sw_init(struct amdgpu_device *adev, int i)
int r;
mutex_init(&adev->vcn.inst[i].vcn1_jpeg1_workaround);
- mutex_init(&adev->vcn.inst[i].vcn_pg_lock);
+ mutex_init(&adev->vcn.inst[i].dpg_lock);
mutex_init(&adev->vcn.inst[i].engine_reset_mutex);
atomic_set(&adev->vcn.inst[i].total_submission_cnt, 0);
INIT_DELAYED_WORK(&adev->vcn.inst[i].idle_work, amdgpu_vcn_idle_work_handler);
@@ -290,7 +290,7 @@ int amdgpu_vcn_sw_fini(struct amdgpu_device *adev, int i)
if (adev->vcn.reg_list)
amdgpu_vcn_reg_dump_fini(adev);
- mutex_destroy(&adev->vcn.inst[i].vcn_pg_lock);
+ mutex_destroy(&adev->vcn.inst[i].dpg_lock);
mutex_destroy(&adev->vcn.inst[i].vcn1_jpeg1_workaround);
return 0;
@@ -419,7 +419,7 @@ static void amdgpu_vcn_idle_work_handler(struct work_struct *work)
unsigned int i = vcn_inst->inst, j;
int r = 0;
- if (adev->vcn.harvest_config & (1 << i))
+ if (adev->vcn.harvest_config & (1 << vcn_inst->inst))
return;
for (j = 0; j < adev->vcn.inst[i].num_enc_rings; ++j)
@@ -427,7 +427,7 @@ static void amdgpu_vcn_idle_work_handler(struct work_struct *work)
/* Only set DPG pause for VCN3 or below, VCN4 and above will be handled by FW */
if (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG &&
- !adev->vcn.inst[i].using_unified_queue) {
+ !vcn_inst->using_unified_queue) {
struct dpg_pause_state new_state;
if (fence[i] ||
@@ -436,18 +436,18 @@ static void amdgpu_vcn_idle_work_handler(struct work_struct *work)
else
new_state.fw_based = VCN_DPG_STATE__UNPAUSE;
- adev->vcn.inst[i].pause_dpg_mode(vcn_inst, &new_state);
+ vcn_inst->pause_dpg_mode(vcn_inst, &new_state);
}
fence[i] += amdgpu_fence_count_emitted(&vcn_inst->ring_dec);
fences += fence[i];
if (!fences && !atomic_read(&vcn_inst->total_submission_cnt)) {
- mutex_lock(&vcn_inst->vcn_pg_lock);
- 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) {
+ vcn_inst->set_pg_state(vcn_inst, AMD_PG_STATE_GATE);
+ adev->vcn.flags &= AMDGPU_VCN_FLAG_VINST_OFF(vcn_inst->inst);
+ if (adev->vcn.workload_profile_active &&
+ !(adev->vcn.flags & AMDGPU_VCN_FLAG_VINST_MASK(adev->vcn.num_vcn_inst))) {
r = amdgpu_dpm_switch_power_profile(adev, PP_SMC_POWER_PROFILE_VIDEO,
false);
if (r)
@@ -470,13 +470,6 @@ 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) {
r = amdgpu_dpm_switch_power_profile(adev, PP_SMC_POWER_PROFILE_VIDEO,
@@ -485,12 +478,14 @@ void amdgpu_vcn_ring_begin_use(struct amdgpu_ring *ring)
dev_warn(adev->dev, "(%d) failed to switch to video power profile mode\n", r);
adev->vcn.workload_profile_active = true;
}
- 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);
+ if (!(adev->vcn.flags & AMDGPU_VCN_FLAG_VINST_ON(vcn_inst->inst))) {
+ vcn_inst->set_pg_state(vcn_inst, AMD_PG_STATE_UNGATE);
+ adev->vcn.flags |= AMDGPU_VCN_FLAG_VINST_ON(vcn_inst->inst);
+ }
+ mutex_unlock(&adev->vcn.workload_profile_mutex);
+ mutex_lock(&vcn_inst->dpg_lock);
/* Only set DPG pause for VCN3 or below, VCN4 and above will be handled by FW */
if (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG &&
!vcn_inst->using_unified_queue) {
@@ -514,7 +509,7 @@ void amdgpu_vcn_ring_begin_use(struct amdgpu_ring *ring)
vcn_inst->pause_dpg_mode(vcn_inst, &new_state);
}
- mutex_unlock(&vcn_inst->vcn_pg_lock);
+ mutex_unlock(&vcn_inst->dpg_lock);
}
void amdgpu_vcn_ring_end_use(struct amdgpu_ring *ring)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
index b3fb1d0e43fc..54cc7646001c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
@@ -320,7 +320,7 @@ struct amdgpu_vcn_inst {
uint8_t vcn_config;
uint32_t vcn_codec_disable_mask;
atomic_t total_submission_cnt;
- struct mutex vcn_pg_lock;
+ struct mutex dpg_lock;
enum amd_powergating_state cur_state;
struct delayed_work idle_work;
unsigned fw_version;
@@ -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 {
diff --git a/drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c b/drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c
index 3a7c137a83ef..4bd0ca26a5ce 100644
--- a/drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c
+++ b/drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c
@@ -147,9 +147,9 @@ static void vcn_v2_5_idle_work_handler(struct work_struct *work)
}
if (!fences && !atomic_read(&adev->vcn.inst[0].total_submission_cnt)) {
+ mutex_lock(&adev->vcn.workload_profile_mutex);
amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_VCN,
AMD_PG_STATE_GATE);
- mutex_lock(&adev->vcn.workload_profile_mutex);
if (adev->vcn.workload_profile_active) {
r = amdgpu_dpm_switch_power_profile(adev, PP_SMC_POWER_PROFILE_VIDEO,
false);
@@ -173,13 +173,6 @@ static void vcn_v2_5_ring_begin_use(struct amdgpu_ring *ring)
cancel_delayed_work_sync(&adev->vcn.inst[0].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) {
r = amdgpu_dpm_switch_power_profile(adev, PP_SMC_POWER_PROFILE_VIDEO,
@@ -188,10 +181,7 @@ static void vcn_v2_5_ring_begin_use(struct amdgpu_ring *ring)
dev_warn(adev->dev, "(%d) failed to switch to video power profile mode\n", r);
adev->vcn.workload_profile_active = true;
}
- mutex_unlock(&adev->vcn.workload_profile_mutex);
-pg_lock:
- mutex_lock(&adev->vcn.inst[0].vcn_pg_lock);
amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_VCN,
AMD_PG_STATE_UNGATE);
@@ -217,7 +207,7 @@ static void vcn_v2_5_ring_begin_use(struct amdgpu_ring *ring)
}
v->pause_dpg_mode(v, &new_state);
}
- mutex_unlock(&adev->vcn.inst[0].vcn_pg_lock);
+ mutex_unlock(&adev->vcn.workload_profile_mutex);
}
static void vcn_v2_5_ring_end_use(struct amdgpu_ring *ring)
--
2.48.1
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