drm/ttm: alter cpu_writers to return -EBUSY in ttm_execbuf_util reservations
This is similar to other platforms that don't allow command submission
to buffers locked on the cpu.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 5ff938d..c6cae73 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -424,8 +424,9 @@
* @no_wait: Return immediately if buffer is busy.
*
* Synchronizes a buffer object for CPU RW access. This means
- * blocking command submission that affects the buffer and
- * waiting for buffer idle. This lock is recursive.
+ * command submission that affects the buffer will return -EBUSY
+ * until ttm_bo_synccpu_write_release is called.
+ *
* Returns
* -EBUSY if the buffer is busy and no_wait is true.
* -ERESTARTSYS if interrupted by a signal.