Am 06.06.2017 um 11:27 schrieb Monk Liu:
> for SR-IOV, we must keep the pipeline-sync in the protection
> of COND_EXEC, otherwise the command consumed by CPG is not
> consistent when world switch triggerd, e.g.:
>
> world switch hit and the IB frame is skipped so the fence
> won't signal, thus CP will jump to the next DMAframe's pipeline-sync
> command, and it will make CP hang foever.
>
> after pipelin-sync moved into COND_EXEC the consistency can be
> guaranteed
>
> Change-Id: I3059535745e2e1215343299b17f27fe081fc01bc
> Signed-off-by: Monk Liu <Monk.Liu at amd.com>
Reviewed-by: Christian König <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 5 +++--
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 7 +++++--
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 2 +-
> 3 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> index 025e03b..947bd34 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> @@ -130,6 +130,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
>
> unsigned i;
> int r = 0;
> + bool need_pipe_sync = false;
>
> if (num_ibs == 0)
> return -EINVAL;
> @@ -165,7 +166,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
> if (ring->funcs->emit_pipeline_sync && job &&
> ((tmp = amdgpu_sync_get_fence(&job->sched_sync)) ||
> amdgpu_vm_need_pipeline_sync(ring, job))) {
> - amdgpu_ring_emit_pipeline_sync(ring);
> + need_pipe_sync = true;
> fence_put(tmp);
> }
>
> @@ -173,7 +174,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
> ring->funcs->insert_start(ring);
>
> if (vm) {
> - r = amdgpu_vm_flush(ring, job);
> + r = amdgpu_vm_flush(ring, job, need_pipe_sync);
> if (r) {
> amdgpu_ring_undo(ring);
> return r;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index b065f8b..6d62e34 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -747,7 +747,7 @@ static bool amdgpu_vm_is_large_bar(struct amdgpu_device *adev)
> *
> * Emit a VM flush when it is necessary.
> */
> -int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job)
> +int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_pipe_sync)
> {
> struct amdgpu_device *adev = ring->adev;
> unsigned vmhub = ring->funcs->vmhub;
> @@ -770,12 +770,15 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job)
> vm_flush_needed = true;
> }
>
> - if (!vm_flush_needed && !gds_switch_needed)
> + if (!vm_flush_needed && !gds_switch_needed && !need_pipe_sync)
> return 0;
>
> if (ring->funcs->init_cond_exec)
> patch_offset = amdgpu_ring_init_cond_exec(ring);
>
> + if (need_pipe_sync)
> + amdgpu_ring_emit_pipeline_sync(ring);
> +
> if (ring->funcs->emit_vm_flush && vm_flush_needed) {
> struct fence *fence;
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index 9aa00d9..cc0009f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -222,7 +222,7 @@ int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
> int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
> struct amdgpu_sync *sync, struct fence *fence,
> struct amdgpu_job *job);
> -int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job);
> +int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_pipe_sync);
> void amdgpu_vm_reset_id(struct amdgpu_device *adev, unsigned vmhub,
> unsigned vmid);
> void amdgpu_vm_reset_all_ids(struct amdgpu_device *adev);
