radeon: fix fence race condition hopefully

For some reason reading the SCRATCH reg from RAM causes some race to occur.
Hopefully fix this.

diff --git a/linux-core/radeon_fence.c b/linux-core/radeon_fence.c
index b662da2..13af804 100644 (file)
--- a/linux-core/radeon_fence.c
+++ b/linux-core/radeon_fence.c
@@ -57,14 +57,15 @@ static void radeon_fence_poll(struct drm_device *dev, uint32_t fence_class,
 {
        struct drm_radeon_private *dev_priv = (struct drm_radeon_private *) dev->dev_private;
        uint32_t sequence;
-        if (waiting_types & DRM_FENCE_TYPE_EXE) {
 
-                sequence = READ_BREADCRUMB(dev_priv);
+       sequence = RADEON_READ(RADEON_SCRATCH_REG3);
+       /* this used to be READ_BREADCRUMB(dev_priv); but it caused
+        * a race somewhere in the fencing irq
+        */
 
-               DRM_DEBUG("polling %d\n", sequence);
-                drm_fence_handler(dev, 0, sequence,
-                                  DRM_FENCE_TYPE_EXE, 0);
-        }
+       DRM_DEBUG("polling %d\n", sequence);
+       drm_fence_handler(dev, 0, sequence,
+                                 DRM_FENCE_TYPE_EXE, 0);
 }
 
 void radeon_fence_handler(struct drm_device * dev)