radeon: Use fences to gate entry to reclocking on <r600

GUI idle interrupts don't seem to work terribly well on r500 and earlier,
so let's use a fence instead.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index bded834afa5d..1ee7fc9918ac 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -76,6 +76,14 @@ static void radeon_pm_set_clocks(struct radeon_device *rdev, int static_switch)
                         msecs_to_jiffies(RADEON_WAIT_IDLE_TIMEOUT));
                 rdev->irq.gui_idle = false;
                 radeon_irq_set(rdev);
+        } else {
+                struct radeon_fence *fence;
+                radeon_ring_alloc(rdev, 64);
+                radeon_fence_create(rdev, &fence);
+                radeon_fence_emit(rdev, fence);
+                radeon_ring_commit(rdev);
+                radeon_fence_wait(fence, false);
+                radeon_fence_unref(&fence);
         }
         radeon_unmap_vram_bos(rdev);