Re: [PATCH 1/8] [media] uvc_video: use ktime_t for stats

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Arnd,

Thank you for the patch.

On Monday, 27 November 2017 15:19:53 EET Arnd Bergmann wrote:
> 'struct timespec' works fine here, but we try to migrate
> away from it in favor of ktime_t or timespec64. In this
> case, using ktime_t produces the simplest code.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/usb/uvc/uvc_video.c | 11 ++++-------
>  drivers/media/usb/uvc/uvcvideo.h  |  4 ++--
>  2 files changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c
> b/drivers/media/usb/uvc/uvc_video.c index fb86d6af398d..d6bee37cd1b8 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -725,7 +725,7 @@ static void uvc_video_stats_decode(struct uvc_streaming
> *stream,
> 
>  	if (stream->stats.stream.nb_frames == 0 &&
>  	    stream->stats.frame.nb_packets == 0)
> -		ktime_get_ts(&stream->stats.stream.start_ts);
> +		stream->stats.stream.start_ts = ktime_get();
> 
>  	switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
>  	case UVC_STREAM_PTS | UVC_STREAM_SCR:
> @@ -865,16 +865,13 @@ size_t uvc_video_stats_dump(struct uvc_streaming
> *stream, char *buf, {
>  	unsigned int scr_sof_freq;
>  	unsigned int duration;
> -	struct timespec ts;
>  	size_t count = 0;
> 
> -	ts = timespec_sub(stream->stats.stream.stop_ts,
> -			  stream->stats.stream.start_ts);
> -
>  	/* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF
>  	 * frequency this will not overflow before more than 1h.
>  	 */
> -	duration = ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
> +	duration = ktime_ms_delta(stream->stats.stream.stop_ts,
> +				  stream->stats.stream.start_ts);
>  	if (duration != 0)
>  		scr_sof_freq = stream->stats.stream.scr_sof_count * 1000
>  			     / duration;
> @@ -915,7 +912,7 @@ static void uvc_video_stats_start(struct uvc_streaming
> *stream)
> 
>  static void uvc_video_stats_stop(struct uvc_streaming *stream)
>  {
> -	ktime_get_ts(&stream->stats.stream.stop_ts);
> +	stream->stats.stream.stop_ts = ktime_get();
>  }
> 
>  /* ------------------------------------------------------------------------
> diff --git a/drivers/media/usb/uvc/uvcvideo.h
> b/drivers/media/usb/uvc/uvcvideo.h index 05398784d1c8..a2c190937067 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -452,8 +452,8 @@ struct uvc_stats_frame {
>  };
> 
>  struct uvc_stats_stream {
> -	struct timespec start_ts;	/* Stream start timestamp */
> -	struct timespec stop_ts;	/* Stream stop timestamp */
> +	ktime_t start_ts;		/* Stream start timestamp */
> +	ktime_t stop_ts;		/* Stream stop timestamp */
> 
>  	unsigned int nb_frames;		/* Number of frames */


-- 
Regards,

Laurent Pinchart