drm/radeon/kms: Fix r600 blit cleanup path

r600 blit cleanup path need to check if a bo was allocated before
trying to free or unpin it. This patch add this check and avoid
oops when the initialization on r6xx or r7xx hw fails.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r600.c

@@ -1961,11 +1961,13 @@ int r600_suspend(struct radeon_device *rdev)
 	r600_wb_disable(rdev);
 	r600_pcie_gart_disable(rdev);
 	/* unpin shaders bo */
+	if (rdev->r600_blit.shader_obj) {
 		r = radeon_bo_reserve(rdev->r600_blit.shader_obj, false);
-	if (unlikely(r != 0))
-		return r;
+		if (!r) {
 			radeon_bo_unpin(rdev->r600_blit.shader_obj);
 			radeon_bo_unreserve(rdev->r600_blit.shader_obj);
+		}
+	}
 	return 0;
 }
 

drivers/gpu/drm/radeon/r600_blit_kms.c

@@ -512,14 +512,16 @@ void r600_blit_fini(struct radeon_device *rdev)
 {
 	int r;
 
+	if (rdev->r600_blit.shader_obj == NULL)
+		return;
+	/* If we can't reserve the bo, unref should be enough to destroy
+	 * it when it becomes idle.
+	 */
 	r = radeon_bo_reserve(rdev->r600_blit.shader_obj, false);
-	if (unlikely(r != 0)) {
-		dev_err(rdev->dev, "(%d) can't finish r600 blit\n", r);
-		goto out_unref;
-	}
+	if (!r) {
 		radeon_bo_unpin(rdev->r600_blit.shader_obj);
 		radeon_bo_unreserve(rdev->r600_blit.shader_obj);
-out_unref:
+	}
 	radeon_bo_unref(&rdev->r600_blit.shader_obj);
 }
 

drivers/gpu/drm/radeon/rv770.c

@@ -975,11 +975,13 @@ int rv770_suspend(struct radeon_device *rdev)
 	r600_wb_disable(rdev);
 	rv770_pcie_gart_disable(rdev);
 	/* unpin shaders bo */
+	if (rdev->r600_blit.shader_obj) {
 		r = radeon_bo_reserve(rdev->r600_blit.shader_obj, false);
 		if (likely(r == 0)) {
 			radeon_bo_unpin(rdev->r600_blit.shader_obj);
 			radeon_bo_unreserve(rdev->r600_blit.shader_obj);
 		}
+	}
 	return 0;
 }