drm/radeon: fix fence driver for dma ring when wb is disabled

The dma ring can't write to register thus have to write to memory
its fence value. This ensure that it doesn't try to use scratch
register for dma ring fence driver.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=58166

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index a76eca18f134..2aaf147969bd 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2533,11 +2533,12 @@ void r600_dma_fence_ring_emit(struct radeon_device *rdev,
 {
         struct radeon_ring *ring = &rdev->ring[fence->ring];
         u64 addr = rdev->fence_drv[fence->ring].gpu_addr;
+
         /* write the fence */
         radeon_ring_write(ring, DMA_PACKET(DMA_PACKET_FENCE, 0, 0, 0));
         radeon_ring_write(ring, addr & 0xfffffffc);
         radeon_ring_write(ring, (upper_32_bits(addr) & 0xff));
-        radeon_ring_write(ring, fence->seq);
+        radeon_ring_write(ring, lower_32_bits(fence->seq));
         /* generate an interrupt */
         radeon_ring_write(ring, DMA_PACKET(DMA_PACKET_TRAP, 0, 0, 0));
 }
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index 22bd6c2c2740..410a975a8eec 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -772,7 +772,7 @@ int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
         int r;
 
         radeon_scratch_free(rdev, rdev->fence_drv[ring].scratch_reg);
-        if (rdev->wb.use_event) {
+        if (rdev->wb.use_event || !radeon_ring_supports_scratch_reg(rdev, &rdev->ring[ring])) {
                 rdev->fence_drv[ring].scratch_reg = 0;
                 index = R600_WB_EVENT_OFFSET + ring * 4;
         } else {