On 2020-03-03 2:03 p.m., James Zhu wrote:
On 2020-03-03 1:44 p.m., Christian König wrote:
Am 03.03.20 um 19:16 schrieb James Zhu:
Fix race condition issue when multiple vcn starts are called.
Signed-off-by: James Zhu <James.Zhu@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 4 ++++
drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
index f96464e..aa7663f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
@@ -63,6 +63,7 @@ int amdgpu_vcn_sw_init(struct amdgpu_device *adev)
int i, r;
INIT_DELAYED_WORK(&adev->vcn.idle_work,
amdgpu_vcn_idle_work_handler);
+ mutex_init(&adev->vcn.vcn_pg_lock);
switch (adev->asic_type) {
case CHIP_RAVEN:
@@ -210,6 +211,7 @@ int amdgpu_vcn_sw_fini(struct amdgpu_device *adev)
}
release_firmware(adev->vcn.fw);
+ mutex_destroy(&adev->vcn.vcn_pg_lock);
return 0;
}
@@ -321,6 +323,7 @@ void amdgpu_vcn_ring_begin_use(struct
amdgpu_ring *ring)
struct amdgpu_device *adev = ring->adev;
bool set_clocks =
!cancel_delayed_work_sync(&adev->vcn.idle_work);
+ mutex_lock(&adev->vcn.vcn_pg_lock);
That still won't work correctly here.
The whole idea of the cancel_delayed_work_sync() and
schedule_delayed_work() dance is that you have exactly one user of
that. If you have multiple rings that whole thing won't work correctly.
To fix this you need to call mutex_lock() before
cancel_delayed_work_sync() and schedule_delayed_work() before
mutex_unlock().
Big lock definitely works. I am trying to use as smaller lock as
possible here. the share resource which needs protect here are power
gate process and dpg mode switch process.
if we move mutex_unlock() before schedule_delayed_work(. I am
wondering what are the other necessary resources which need protect.
By the way, cancel_delayed_work_sync() supports multiple thread itself,
so I didn't put it into protection area. power gate is shared by all
VCN IP instances and different rings , so it needs be put into
protection area.
each ring's job itself is serialized by scheduler. it doesn't need be
put into this protection area.
Thanks!
James
Regards,
Christian.
if (set_clocks) {
amdgpu_gfx_off_ctrl(adev, false);
amdgpu_device_ip_set_powergating_state(adev,
AMD_IP_BLOCK_TYPE_VCN,
@@ -345,6 +348,7 @@ void amdgpu_vcn_ring_begin_use(struct
amdgpu_ring *ring)
adev->vcn.pause_dpg_mode(adev, ring->me, &new_state);
}
+ mutex_unlock(&adev->vcn.vcn_pg_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 6fe0573..2ae110d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
@@ -200,6 +200,7 @@ struct amdgpu_vcn {
struct drm_gpu_scheduler
*vcn_dec_sched[AMDGPU_MAX_VCN_INSTANCES];
uint32_t num_vcn_enc_sched;
uint32_t num_vcn_dec_sched;
+ struct mutex vcn_pg_lock;
unsigned harvest_config;
int (*pause_dpg_mode)(struct amdgpu_device *adev,
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