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Date:   Fri, 30 Dec 2022 15:36:51 +0200
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Ricardo Ribalda <ribalda@chromium.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        "hn.chen" <hn.chen@sunplusit.com>, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND v2 1/8] media: uvc: Extend documentation of
 uvc_video_clock_decode()
Message-ID: <Y67pc3ZEoteZ0S2l@pendragon.ideasonboard.com>
References: <20220920-resend-hwtimestamp-v2-0-0d7978a817cc@chromium.org>
 <20220920-resend-hwtimestamp-v2-1-0d7978a817cc@chromium.org>
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Hi Ricardo,

Thank you for the patch.

s/uvc/uvcvideo/ in the subject line.

On Fri, Dec 02, 2022 at 06:02:41PM +0100, Ricardo Ribalda wrote:
> Make a explicit reference to uvc 1.5, explaining how the algorithm

s/a explicit/an explicit/
s/uvc/UVC/

> supports the different behaviour of uvc 1.1 and 1.5.

Ditto.

> Tested-by: HungNien Chen <hn.chen@sunplusit.com>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>  drivers/media/usb/uvc/uvc_video.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 170a008f4006..ab56e65ca324 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -517,6 +517,9 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
>  	/*
>  	 * To limit the amount of data, drop SCRs with an SOF identical to the
>  	 * previous one.
> +	 * This filtering is also needed for supporting UVC 1.5. Where all the
> +	 * data packages of the same frame contains the same sof. In that case
> +	 * only the first one will match the host_sof.

  	 * To limit the amount of data, drop SCRs with an SOF identical to the
  	 * previous one. This filtering is also needed to support UVC 1.5, where
	 * all the data packets of the same frame contains the same SOF. In that
	 * case only the first one will match the host_sof.

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

I can fix this when applying if there's no other need to submit a v3.

>  	 */
>  	dev_sof = get_unaligned_le16(&data[header_size - 2]);
>  	if (dev_sof == stream->clock.last_sof)
> 

-- 
Regards,

Laurent Pinchart