drm/amdgpu: switch the GDS only on demand v2

Switching the GDS space to often seems to be problematic.

This patch together with the following can avoid VM faults on context switch.

v2: extend commit message a bit

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Reviewed-by: Chunming Zhou <david1.zhou@amd.com> (v1)

1 files changed, 41 insertions, 2 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 5fab5b25b935..8642a1ccd6c3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -252,16 +252,53 @@ void amdgpu_vm_flush(struct amdgpu_ring *ring,
 		     uint32_t gws_base, uint32_t gws_size,
 		     uint32_t oa_base, uint32_t oa_size)
 {
+	struct amdgpu_device *adev = ring->adev;
+	struct amdgpu_vm_manager_id *mgr_id = &adev->vm_manager.ids[vm_id];
+
 	if (pd_addr != AMDGPU_VM_NO_FLUSH) {
 		trace_amdgpu_vm_flush(pd_addr, ring->idx, vm_id);
 		amdgpu_ring_emit_vm_flush(ring, vm_id, pd_addr);
 	}
 
-	if (ring->funcs->emit_gds_switch)
+	if (ring->funcs->emit_gds_switch && (
+	    mgr_id->gds_base != gds_base ||
+	    mgr_id->gds_size != gds_size ||
+	    mgr_id->gws_base != gws_base ||
+	    mgr_id->gws_size != gws_size ||
+	    mgr_id->oa_base != oa_base ||
+	    mgr_id->oa_size != oa_size)) {
+
+		mgr_id->gds_base = gds_base;
+		mgr_id->gds_size = gds_size;
+		mgr_id->gws_base = gws_base;
+		mgr_id->gws_size = gws_size;
+		mgr_id->oa_base = oa_base;
+		mgr_id->oa_size = oa_size;
 		amdgpu_ring_emit_gds_switch(ring, vm_id,
 					    gds_base, gds_size,
 					    gws_base, gws_size,
 					    oa_base, oa_size);
+	}
+}
+
+/**
+ * amdgpu_vm_reset_id - reset VMID to zero
+ *
+ * @adev: amdgpu device structure
+ * @vm_id: vmid number to use
+ *
+ * Reset saved GDW, GWS and OA to force switch on next flush.
+ */
+void amdgpu_vm_reset_id(struct amdgpu_device *adev, unsigned vm_id)
+{
+	struct amdgpu_vm_manager_id *mgr_id = &adev->vm_manager.ids[vm_id];
+
+	mgr_id->gds_base = 0;
+	mgr_id->gds_size = 0;
+	mgr_id->gws_base = 0;
+	mgr_id->gws_size = 0;
+	mgr_id->oa_base = 0;
+	mgr_id->oa_size = 0;
 }
 
 /**
@@ -1425,9 +1462,11 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev)
 	INIT_LIST_HEAD(&adev->vm_manager.ids_lru);
 
 	/* skip over VMID 0, since it is the system VM */
-	for (i = 1; i < adev->vm_manager.num_ids; ++i)
+	for (i = 1; i < adev->vm_manager.num_ids; ++i) {
+		amdgpu_vm_reset_id(adev, i);
 		list_add_tail(&adev->vm_manager.ids[i].list,
 			      &adev->vm_manager.ids_lru);
+	}
 
 	atomic_set(&adev->vm_manager.vm_pte_next_ring, 0);
 }