Hi Michael On Mon, 18 Mar 2024 at 10:28, Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> wrote: > > When the uvc request will get parsed by uvc_video_decode_start it will > leave the function with -EAGAIN to be restarted on the next frame. While > the first wrong parse the statistics will already be updated with > uvc_video_stats_decode. > > One value e.g. is the error_count, which therefor will be incremented > twice in case the fid has changed on the way. This patch fixes the > unnecessary extra parsing by moving the decode functions to the > end of decode_start, when it is save to really parse the data. nit: safe > > Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> Reviewed-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > --- > Changes in v3: > - Moved the clock_decode and stat_decode to end of function as suggested by Ricardo Ribalda > - Link to v2: https://lore.kernel.org/r/20240221-uvc-host-video-decode-start-v2-1-88c6e17e487a@xxxxxxxxxxxxxx > > Changes in v2: > - Moved the EAGAIN bailout after the sequence handling as mentioned by Ricardo Ribalda > - Link to v1: https://lore.kernel.org/r/20240221-uvc-host-video-decode-start-v1-1-228995925c70@xxxxxxxxxxxxxx > --- > drivers/media/usb/uvc/uvc_video.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > index 7cbf4692bd875..7471bff0ca894 100644 > --- a/drivers/media/usb/uvc/uvc_video.c > +++ b/drivers/media/usb/uvc/uvc_video.c > @@ -1078,9 +1078,6 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, > uvc_video_stats_update(stream); > } > > - uvc_video_clock_decode(stream, buf, data, len); > - uvc_video_stats_decode(stream, data, len); > - > /* > * Store the payload FID bit and return immediately when the buffer is > * NULL. > @@ -1147,6 +1144,9 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, > return -EAGAIN; > } > > + uvc_video_clock_decode(stream, buf, data, len); > + uvc_video_stats_decode(stream, data, len); > + > stream->last_fid = fid; > > return data[0]; > > --- > base-commit: d99e42ce6b8341d3f09e22c6706461ec900fe172 > change-id: 20240221-uvc-host-video-decode-start-af53df5924cd > > Best regards, > -- > Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > > -- Ricardo Ribalda
