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Message-ID: <Y674PksMsjOqNG7Q@pendragon.ideasonboard.com>
Date: Fri, 30 Dec 2022 16:39:58 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Ricardo Ribalda <ribalda@...omium.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
"hn.chen" <hn.chen@...plusit.com>, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v2 7/8] media: uvcvideo: Refactor clock circular
buffer
Hi Ricardo,
Thank you for the patch.
On Fri, Dec 02, 2022 at 06:02:47PM +0100, Ricardo Ribalda wrote:
> Move the addition to the buffer into its own function and remove the
> stream dependency to all the clock functions.
Commit messages need to explain *why* the commit performs a change, not
just how.
> Tested-by: HungNien Chen <hn.chen@...plusit.com>
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> ---
> drivers/media/usb/uvc/uvc_video.c | 81 ++++++++++++++++++---------------------
> 1 file changed, 37 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 7c6448c6d706..c81a8362d582 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -464,18 +464,29 @@ static inline ktime_t uvc_video_get_time(void)
> return ktime_get_real();
> }
>
> +static void uvc_video_clock_add_sample(struct uvc_clock *clock,
> + const struct uvc_clock_sample *sample)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&clock->lock, flags);
> +
> + memcpy(&clock->samples[clock->head], sample, sizeof(*sample));
> + clock->last_sof = sample->dev_sof;
> + clock->head = (clock->head + 1) % clock->size;
> + clock->count = min(clock->count + 1, clock->size);
> +
> + spin_unlock_irqrestore(&clock->lock, flags);
> +}
> +
> static void
> uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
> const u8 *data, int len)
> {
> - struct uvc_clock_sample *sample;
> + struct uvc_clock_sample sample;
> unsigned int header_size;
> bool has_pts = false;
> bool has_scr = false;
> - unsigned long flags;
> - ktime_t time;
> - u16 host_sof;
> - u16 dev_sof;
>
> switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
> case UVC_STREAM_PTS | UVC_STREAM_SCR:
> @@ -530,20 +541,19 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
> * only the first one will match the host_sof.
> */
> if (stream->dev->quirks & UVC_QUIRK_INVALID_DEVICE_SOF)
> - dev_sof = usb_get_current_frame_number(stream->dev->udev);
> + sample.dev_sof =
> + usb_get_current_frame_number(stream->dev->udev);
> else
> - dev_sof = get_unaligned_le16(&data[header_size - 2]);
> + sample.dev_sof = get_unaligned_le16(&data[header_size - 2]);
>
> - if (dev_sof == stream->clock.last_sof)
> + if (sample.dev_sof == stream->clock.last_sof)
> return;
>
> - stream->clock.last_sof = dev_sof;
> -
> if (stream->dev->quirks & UVC_QUIRK_INVALID_DEVICE_SOF)
> - host_sof = dev_sof;
> + sample.host_sof = sample.dev_sof;
> else
> - host_sof = usb_get_current_frame_number(stream->dev->udev);
> - time = uvc_video_get_time();
> + sample.host_sof = usb_get_current_frame_number(stream->dev->udev);
> + sample.host_time = uvc_video_get_time();
>
> /*
> * The UVC specification allows device implementations that can't obtain
> @@ -566,46 +576,29 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
> * the 8 LSBs of the delta are kept.
> */
> if (stream->clock.sof_offset == (u16)-1) {
> - u16 delta_sof = (host_sof - dev_sof) & 255;
> + u16 delta_sof = (sample.host_sof - sample.dev_sof) & 255;
> if (delta_sof >= 10)
> stream->clock.sof_offset = delta_sof;
> else
> stream->clock.sof_offset = 0;
> }
>
> - dev_sof = (dev_sof + stream->clock.sof_offset) & 2047;
> -
> - spin_lock_irqsave(&stream->clock.lock, flags);
> -
> - sample = &stream->clock.samples[stream->clock.head];
> - sample->dev_stc = get_unaligned_le32(&data[header_size - 6]);
> - sample->dev_sof = dev_sof;
> - sample->host_sof = host_sof;
> - sample->host_time = time;
> -
> - /* Update the sliding window head and count. */
> - stream->clock.head = (stream->clock.head + 1) % stream->clock.size;
> + sample.dev_sof = (sample.dev_sof + stream->clock.sof_offset) & 2047;
> + sample.dev_stc = get_unaligned_le32(&data[header_size - 6]);
>
> - if (stream->clock.count < stream->clock.size)
> - stream->clock.count++;
> -
> - spin_unlock_irqrestore(&stream->clock.lock, flags);
> + uvc_video_clock_add_sample(&stream->clock, &sample);
> }
>
> -static void uvc_video_clock_reset(struct uvc_streaming *stream)
> +static void uvc_video_clock_reset(struct uvc_clock *clock)
> {
> - struct uvc_clock *clock = &stream->clock;
> -
> clock->head = 0;
> clock->count = 0;
> clock->last_sof = -1;
> clock->sof_offset = -1;
> }
>
> -static int uvc_video_clock_init(struct uvc_streaming *stream)
> +static int uvc_video_clock_init(struct uvc_clock *clock)
> {
> - struct uvc_clock *clock = &stream->clock;
> -
> spin_lock_init(&clock->lock);
> clock->size = 32;
>
> @@ -614,15 +607,15 @@ static int uvc_video_clock_init(struct uvc_streaming *stream)
> if (clock->samples == NULL)
> return -ENOMEM;
>
> - uvc_video_clock_reset(stream);
> + uvc_video_clock_reset(clock);
>
> return 0;
> }
>
> -static void uvc_video_clock_cleanup(struct uvc_streaming *stream)
> +static void uvc_video_clock_cleanup(struct uvc_clock *clock)
> {
> - kfree(stream->clock.samples);
> - stream->clock.samples = NULL;
> + kfree(clock->samples);
> + clock->samples = NULL;
> }
>
> /*
> @@ -2085,7 +2078,7 @@ int uvc_video_resume(struct uvc_streaming *stream, int reset)
>
> stream->frozen = 0;
>
> - uvc_video_clock_reset(stream);
> + uvc_video_clock_reset(&stream->clock);
>
> if (!uvc_queue_streaming(&stream->queue))
> return 0;
> @@ -2219,7 +2212,7 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> {
> int ret;
>
> - ret = uvc_video_clock_init(stream);
> + ret = uvc_video_clock_init(&stream->clock);
> if (ret < 0)
> return ret;
>
> @@ -2237,7 +2230,7 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> error_video:
> usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> error_commit:
> - uvc_video_clock_cleanup(stream);
> + uvc_video_clock_cleanup(&stream->clock);
>
> return ret;
> }
> @@ -2265,5 +2258,5 @@ void uvc_video_stop_streaming(struct uvc_streaming *stream)
> usb_clear_halt(stream->dev->udev, pipe);
> }
>
> - uvc_video_clock_cleanup(stream);
> + uvc_video_clock_cleanup(&stream->clock);
> }
>
--
Regards,
Laurent Pinchart
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