[v2,1/8] media: uvc: Extend documentation of uvc_video_clock_decode()

Message ID 20220920-resend-hwtimestamp-v2-1-d8d0616bb612@chromium.org
State New
Headers
Series uvcvideo: Fixes for hw timestamping |

Commit Message

Ricardo Ribalda Nov. 3, 2022, 1:40 p.m. UTC
  Make a explicit reference to uvc 1.5, explaining how the algorithm
supports the different behaviour of uvc 1.1 and 1.5.

Tested-by: HungNien Chen <hn.chen@sunplusit.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
  

Patch

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