[PATCH 5/8] drm/amdgpu/sdma: Clear SDMA rings after reset before starting them

["Timur Kristóf" <timur.kristof@gmail.com>]

The ring contains commands that were emitted before the reset.
These need to be cleared to make sure the HW doesn't execute
them, because they are garbage at this point.

Note that the ring reset helpers will re-emit the commands
that are necessary after the reset.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
index fbac732f3e01..66f278f77f71 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
@@ -593,6 +593,18 @@ int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id,
 		goto exit;
 	}
 
+	amdgpu_ring_clear_ring(gfx_ring);
+	gfx_ring->wptr = 0;
+	atomic64_set((atomic64_t *)gfx_ring->wptr_cpu_addr, 0);
+	atomic64_set((atomic64_t *)gfx_ring->rptr_cpu_addr, 0);
+
+	if (adev->sdma.has_page_queue) {
+		amdgpu_ring_clear_ring(page_ring);
+		page_ring->wptr = 0;
+		atomic64_set((atomic64_t *)page_ring->wptr_cpu_addr, 0);
+		atomic64_set((atomic64_t *)page_ring->rptr_cpu_addr, 0);
+	}
+
 	if (sdma_instance->funcs->start_kernel_queue) {
 		sdma_instance->funcs->start_kernel_queue(gfx_ring);
 		if (adev->sdma.has_page_queue)
-- 
2.55.0