v4l2: free kernel buffers before allocating new ones

See https://bugzilla.gnome.org/show_bug.cgi?id=670257

diff --git a/sys/v4l2/gstv4l2bufferpool.c b/sys/v4l2/gstv4l2bufferpool.c
index 0679ea3..65d1a5c 100644 (file)
--- a/sys/v4l2/gstv4l2bufferpool.c
+++ b/sys/v4l2/gstv4l2bufferpool.c
@@ -305,6 +305,17 @@ gst_v4l2_buffer_pool_set_config (GstBufferPool * bpool, GstStructure * config)
       else
         num_buffers = max_buffers;
 
+      /* Free the buffers from the kernel */
+      GST_DEBUG_OBJECT (pool, "Freeing the buffers from the kernel");
+
+      memset (&breq, 0, sizeof (struct v4l2_requestbuffers));
+      breq.type = obj->type;
+      breq.count = 0;
+      breq.memory = V4L2_MEMORY_MMAP;
+
+      if (v4l2_ioctl (pool->video_fd, VIDIOC_REQBUFS, &breq) < 0)
+        goto reqbufs_failed;
+
       /* first, lets request buffers, and see how many we can get: */
       GST_DEBUG_OBJECT (pool, "starting, requesting %d MMAP buffers",
           num_buffers);