linux-kernel - [PATCH 3.10 45/77] media: uvcvideo: Fix clock param realtime setting

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Message-Id: <20140628174523.875022250@linuxfoundation.org>
Date:	Sat, 28 Jun 2014 10:46:38 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Olivier Langlois <olivier@...llion01.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Mauro Carvalho Chehab <m.chehab@...sung.com>
Subject: [PATCH 3.10 45/77] media: uvcvideo: Fix clock param realtime setting

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Olivier Langlois <olivier@...llion01.com>

commit 3b35fc81e7ec552147a4fd843d0da0bbbe4ef253 upstream.

timestamps in v4l2 buffers returned to userspace are updated in
uvc_video_clock_update() which uses timestamps fetched from
uvc_video_clock_decode() by calling unconditionally ktime_get_ts().

Hence setting the module clock param to realtime has no effect before
this patch.

This has been tested with ffmpeg:

ffmpeg -y -f v4l2 -input_format yuyv422 -video_size 640x480 -framerate 30 -i /dev/video0 \
 -f alsa -acodec pcm_s16le -ar 16000 -ac 1 -i default \
 -c:v libx264 -preset ultrafast \
 -c:a libfdk_aac \
 out.mkv

and inspecting the v4l2 input starting timestamp.

Signed-off-by: Olivier Langlois <olivier@...llion01.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@...sung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/media/usb/uvc/uvc_video.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -361,6 +361,14 @@ static int uvc_commit_video(struct uvc_s
  * Clocks and timestamps
  */
 
+static inline void uvc_video_get_ts(struct timespec *ts)
+{
+	if (uvc_clock_param == CLOCK_MONOTONIC)
+		ktime_get_ts(ts);
+	else
+		ktime_get_real_ts(ts);
+}
+
 static void
 uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
 		       const __u8 *data, int len)
@@ -420,7 +428,7 @@ uvc_video_clock_decode(struct uvc_stream
 	stream->clock.last_sof = dev_sof;
 
 	host_sof = usb_get_current_frame_number(stream->dev->udev);
-	ktime_get_ts(&ts);
+	uvc_video_get_ts(&ts);
 
 	/* The UVC specification allows device implementations that can't obtain
 	 * the USB frame number to keep their own frame counters as long as they
@@ -1010,10 +1018,7 @@ static int uvc_video_decode_start(struct
 			return -ENODATA;
 		}
 
-		if (uvc_clock_param == CLOCK_MONOTONIC)
-			ktime_get_ts(&ts);
-		else
-			ktime_get_real_ts(&ts);
+		uvc_video_get_ts(&ts);
 
 		buf->buf.v4l2_buf.sequence = stream->sequence;
 		buf->buf.v4l2_buf.timestamp.tv_sec = ts.tv_sec;


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