[PATCH] amdgpu: fix multi-process hang issue

[Emily Deng]

From: Monk Liu <Monk.Liu at amd.com>

SWDEV-146499: hang during multi vulkan process testing

cause:
the second frame's PREAMBLE_IB have clear-state
and LOAD actions, those actions ruin the pipeline
that is still doing process in the previous frame's
work-load IB.

fix:
need insert pipeline sync if have context switch for
SRIOV (because only SRIOV will report PREEMPTION flag
to UMD)

Change-Id: If676da7a9b0147114cd76d19b6035ed8033de449
Signed-off-by: Monk Liu <Monk.Liu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
index 5c22cfd..66efa85 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
@@ -95,6 +95,12 @@ void amdgpu_ib_free(struct amdgpu_device *adev, struct amdgpu_ib *ib,
 	amdgpu_sa_bo_free(adev, &ib->sa_bo, f);
 }
 
+static bool amdgpu_ib_has_preamble(struct amdgpu_ring *ring, bool ctx_switch) {
+	return (amdgpu_sriov_vf(ring->adev) &&
+			ring->funcs->type == AMDGPU_RING_TYPE_GFX &&
+			ctx_switch);
+}
+
 /**
  * amdgpu_ib_schedule - schedule an IB (Indirect Buffer) on the ring
  *
@@ -123,7 +129,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 	struct amdgpu_device *adev = ring->adev;
 	struct amdgpu_ib *ib = &ibs[0];
 	struct dma_fence *tmp = NULL;
-	bool skip_preamble, need_ctx_switch;
+	bool need_ctx_switch;
 	unsigned patch_offset = ~0;
 	struct amdgpu_vm *vm;
 	uint64_t fence_ctx;
@@ -156,6 +162,8 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 		return -EINVAL;
 	}
 
+	need_ctx_switch = ring->current_ctx != fence_ctx;
+
 	alloc_size = ring->funcs->emit_frame_size + num_ibs *
 		ring->funcs->emit_ib_size;
 
@@ -167,6 +175,7 @@ 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, NULL)) ||
+		 amdgpu_ib_has_preamble(ring, need_ctx_switch) ||
 	     amdgpu_vm_need_pipeline_sync(ring, job))) {
 		need_pipe_sync = true;
 
@@ -200,8 +209,6 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 			amdgpu_asic_flush_hdp(adev, ring);
 	}
 
-	skip_preamble = ring->current_ctx == fence_ctx;
-	need_ctx_switch = ring->current_ctx != fence_ctx;
 	if (job && ring->funcs->emit_cntxcntl) {
 		if (need_ctx_switch)
 			status |= AMDGPU_HAVE_CTX_SWITCH;
@@ -215,7 +222,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
 
 		/* drop preamble IBs if we don't have a context switch */
 		if ((ib->flags & AMDGPU_IB_FLAG_PREAMBLE) &&
-			skip_preamble &&
+			!need_ctx_switch &&
 			!(status & AMDGPU_PREAMBLE_IB_PRESENT_FIRST) &&
 			!amdgpu_sriov_vf(adev)) /* for SRIOV preemption, Preamble CE ib must be inserted anyway */
 			continue;
-- 
2.7.4