From c4df4a037138a2f1f16bbf1762aa72bcf1ae11f5 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Thu, 7 Nov 2024 15:42:33 +0100
Subject: [PATCH] v4l2: improve debug a little

---
 spa/plugins/v4l2/v4l2-utils.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/spa/plugins/v4l2/v4l2-utils.c b/spa/plugins/v4l2/v4l2-utils.c
index 0c97628c3..95f74da96 100644
--- a/spa/plugins/v4l2/v4l2-utils.c
+++ b/spa/plugins/v4l2/v4l2-utils.c
@@ -1415,6 +1415,8 @@ static int mmap_read(struct impl *this)
 	if (xioctl(dev->fd, VIDIOC_DQBUF, &buf) < 0)
 		return -errno;
 
+	spa_log_trace(this->log, "v4l2 %p: have output %d/%d", this, buf.index, buf.sequence);
+
 	/* Drop the first frame in order to work around common firmware
 	 * timestamp issues */
 	if (port->first_buffer) {
@@ -1425,7 +1427,6 @@ static int mmap_read(struct impl *this)
 	}
 
 	pts = SPA_TIMEVAL_TO_NSEC(&buf.timestamp);
-	spa_log_trace(this->log, "v4l2 %p: have output %d", this, buf.index);
 
 	if (this->clock) {
 		/* FIXME, we should follow the driver clock and target_ values.
@@ -1474,6 +1475,7 @@ static void v4l2_on_fd_events(struct spa_source *source)
 	struct spa_io_buffers *io;
 	struct port *port = &this->out_ports[0];
 	struct buffer *b;
+	int res;
 
 	if (source->rmask & SPA_IO_ERR) {
 		struct port *port = &this->out_ports[0];
@@ -1488,8 +1490,10 @@ static void v4l2_on_fd_events(struct spa_source *source)
 		return;
 	}
 
-	if (mmap_read(this) < 0)
+	if ((res = mmap_read(this)) < 0) {
+		spa_log_warn(this->log, "v4l2 %p: mmap read error:%s", this, spa_strerror(res));
 		return;
+	}
 
 	if (spa_list_is_empty(&port->queue))
 		return;