From ef99179710d6ec04d6783afdf8387523c7087920 Mon Sep 17 00:00:00 2001 From: Andy Walls Date: Thu, 31 Dec 2009 18:27:13 -0300 Subject: 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 Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/cx18/cx18-streams.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'drivers/media/video/cx18/cx18-streams.c') diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c index 9755f4416e96..680e7da5e5e4 100644 --- a/drivers/media/video/cx18/cx18-streams.c +++ b/drivers/media/video/cx18/cx18-streams.c @@ -463,6 +463,32 @@ static void cx18_vbi_setup(struct cx18_stream *s) 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) -- cgit v1.2.3