V4L/DVB (13907): cx18: Perform automatic rotation of very old, unread IDX buffers
According to the v4l2 spec, very old MPEG index entries needs to be discarded
in favor of newer index entries. This change ensures the firmware always has
buffers for index entries at the expense of the oldest unread buffers.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index 9755f44..680e7da 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -463,6 +463,32 @@
cx18_api(cx, CX18_CPU_SET_RAW_VBI_PARAM, 6, data);
}
+void cx18_stream_rotate_idx_mdls(struct cx18 *cx)
+{
+ struct cx18_stream *s = &cx->streams[CX18_ENC_STREAM_TYPE_IDX];
+ struct cx18_mdl *mdl;
+
+ if (!cx18_stream_enabled(s))
+ return;
+
+ /* Return if the firmware is not running low on MDLs */
+ if ((atomic_read(&s->q_free.depth) + atomic_read(&s->q_busy.depth)) >=
+ CX18_ENC_STREAM_TYPE_IDX_FW_MDL_MIN)
+ return;
+
+ /* Return if there are no MDLs to rotate back to the firmware */
+ if (atomic_read(&s->q_full.depth) < 2)
+ return;
+
+ /*
+ * Take the oldest IDX MDL still holding data, and discard its index
+ * entries by scheduling the MDL to go back to the firmware
+ */
+ mdl = cx18_dequeue(s, &s->q_full);
+ if (mdl != NULL)
+ cx18_enqueue(s, mdl, &s->q_free);
+}
+
static
struct cx18_queue *_cx18_stream_put_mdl_fw(struct cx18_stream *s,
struct cx18_mdl *mdl)