v4l2: also poll for output devices

Note that the V4L2 API defines that for output devices POLLOUT
indicates that a buffer is ready to be dequeued.

https://bugzilla.gnome.org/show_bug.cgi?id=698992

diff --git a/sys/v4l2/gstv4l2bufferpool.c b/sys/v4l2/gstv4l2bufferpool.c
index f885156..53e3700 100644 (file)
--- a/sys/v4l2/gstv4l2bufferpool.c
+++ b/sys/v4l2/gstv4l2bufferpool.c
@@ -632,13 +632,8 @@ gst_v4l2_buffer_pool_dqbuf (GstV4l2BufferPool * pool, GstBuffer ** buffer)
   GstV4l2Object *obj = pool->obj;
   GstClockTime timestamp;
 
-  if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
-    /* select works for input devices when data is available. According to the
-     * specs we can also poll to find out when a frame has been displayed but
-     * that just seems to lock up here */
-    if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
-      goto poll_error;
-  }
+  if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
+    goto poll_error;
 
   memset (&vbuffer, 0x00, sizeof (vbuffer));
   vbuffer.type = obj->type;

diff --git a/sys/v4l2/v4l2_calls.c b/sys/v4l2/v4l2_calls.c
index e9201a2..21262ba 100644 (file)
--- a/sys/v4l2/v4l2_calls.c
+++ b/sys/v4l2/v4l2_calls.c
@@ -481,7 +481,10 @@ gst_v4l2_open (GstV4l2Object * v4l2object)
 
   pollfd.fd = v4l2object->video_fd;
   gst_poll_add_fd (v4l2object->poll, &pollfd);
-  gst_poll_fd_ctl_read (v4l2object->poll, &pollfd, TRUE);
+  if (v4l2object->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
+    gst_poll_fd_ctl_read (v4l2object->poll, &pollfd, TRUE);
+  else
+    gst_poll_fd_ctl_write (v4l2object->poll, &pollfd, TRUE);
 
   return TRUE;