From a9b191971ca0c7106fc290d41014e38eb5d30fbd Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Thu, 19 Mar 2020 13:15:49 +0100
Subject: [PATCH] v4l2: fix buffer recycle

Only set the OUTSTANDING flag when we placed the buffer in an
io area and need to recycle it later.
When we captured a frame, put it in the queue. Then dequeue it
into the io area after recycling buffers.

Fixes #217
---
 spa/plugins/v4l2/v4l2-source.c |  1 +
 spa/plugins/v4l2/v4l2-utils.c  | 37 ++++++++++++++++++++--------------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/spa/plugins/v4l2/v4l2-source.c b/spa/plugins/v4l2/v4l2-source.c
index 4f429e00d..9f2454d16 100644
--- a/spa/plugins/v4l2/v4l2-source.c
+++ b/spa/plugins/v4l2/v4l2-source.c
@@ -859,6 +859,7 @@ static int impl_node_process(void *object)
 
 	b = spa_list_first(&port->queue, struct buffer, link);
 	spa_list_remove(&b->link);
+	SPA_FLAG_SET(b->flags, BUFFER_FLAG_OUTSTANDING);
 
 	spa_log_trace(this->log, NAME " %p: dequeue buffer %d", this, b->id);
 
diff --git a/spa/plugins/v4l2/v4l2-utils.c b/spa/plugins/v4l2/v4l2-utils.c
index a8b5ee87f..4bbc27259 100644
--- a/spa/plugins/v4l2/v4l2-utils.c
+++ b/spa/plugins/v4l2/v4l2-utils.c
@@ -1165,7 +1165,6 @@ static int mmap_read(struct impl *this)
 {
 	struct port *port = &this->out_ports[0];
 	struct spa_v4l2_device *dev = &port->dev;
-	struct spa_io_buffers *io;
 	struct v4l2_buffer buf;
 	struct buffer *b;
 	struct spa_data *d;
@@ -1210,26 +1209,16 @@ static int mmap_read(struct impl *this)
 	if (buf.flags & V4L2_BUF_FLAG_ERROR)
 		d[0].flags |= SPA_CHUNK_FLAG_CORRUPTED;
 
-	SPA_FLAG_SET(b->flags, BUFFER_FLAG_OUTSTANDING);
-
-	io = port->io;
-	if (io != NULL && io->status != SPA_STATUS_HAVE_DATA) {
-		io->buffer_id = b->id;
-		io->status = SPA_STATUS_HAVE_DATA;
-	}
-	else {
-		spa_list_append(&port->queue, &b->link);
-	}
-
-	spa_log_trace(this->log, "v4l2 %p: now queued %d", this, b->id);
-	spa_node_call_ready(&this->callbacks, SPA_STATUS_HAVE_DATA);
-
+	spa_list_append(&port->queue, &b->link);
 	return 0;
 }
 
 static void v4l2_on_fd_events(struct spa_source *source)
 {
 	struct impl *this = source->data;
+	struct spa_io_buffers *io;
+	struct port *port = &this->out_ports[0];
+	struct buffer *b;
 
 	if (source->rmask & SPA_IO_ERR) {
 		struct port *port = &this->out_ports[0];
@@ -1246,6 +1235,24 @@ static void v4l2_on_fd_events(struct spa_source *source)
 
 	if (mmap_read(this) < 0)
 		return;
+
+	if (spa_list_is_empty(&port->queue))
+		return;
+
+	io = port->io;
+	if (io != NULL && io->status != SPA_STATUS_HAVE_DATA) {
+		if (io->buffer_id < port->n_buffers)
+			spa_v4l2_buffer_recycle(this, io->buffer_id);
+
+		b = spa_list_first(&port->queue, struct buffer, link);
+		spa_list_remove(&b->link);
+		SPA_FLAG_SET(b->flags, BUFFER_FLAG_OUTSTANDING);
+
+		io->buffer_id = b->id;
+		io->status = SPA_STATUS_HAVE_DATA;
+		spa_log_trace(this->log, "v4l2 %p: now queued %d", this, b->id);
+	}
+	spa_node_call_ready(&this->callbacks, SPA_STATUS_HAVE_DATA);
 }
 
 static int spa_v4l2_use_buffers(struct impl *this, struct spa_buffer **buffers, uint32_t n_buffers)