tech@,

I'd like to clearify which timestamps have we used in v4l2 buffers in
both drivers: utvfu and uvideo, which uses the same logic.

V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC and V4L2_BUF_FLAG_TSTAMP_SRC_EOF mean
that timestamp has been taken from CLOCK_MONOTONIC when the last pixel
of the frame was read from device, and not before the first one.

Thus, I had explicity unset V4L2_BUF_FLAG_TIMECODE bit if application
requested it, because it isn't supported.

Ok?

Index: sys/dev/usb/utvfu.c
===================================================================
RCS file: /home/cvs/src/sys/dev/usb/utvfu.c,v
diff -u -p -r1.22 utvfu.c
--- sys/dev/usb/utvfu.c	15 Jan 2025 20:34:50 -0000	1.22
+++ sys/dev/usb/utvfu.c	25 Feb 2025 17:45:24 -0000
@@ -1378,7 +1378,12 @@ utvfu_mmap_queue(struct utvfu_softc *sc,
 	sc->sc_mmap[i].v4l2_buf.bytesused = len;
 
 	/* timestamp it */
-	getmicrotime(&sc->sc_mmap[i].v4l2_buf.timestamp);
+	getmicrouptime(&sc->sc_mmap[i].v4l2_buf.timestamp);
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TIMESTAMP_MASK;
+	sc->sc_mmap[i].v4l2_buf.flags |= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
+	sc->sc_mmap[i].v4l2_buf.flags |= V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TIMECODE;
 
 	/* appropriately set/clear flags */
 	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_QUEUED;
Index: sys/dev/usb/uvideo.c
===================================================================
RCS file: /home/cvs/src/sys/dev/usb/uvideo.c,v
diff -u -p -r1.242 uvideo.c
--- sys/dev/usb/uvideo.c	24 Feb 2025 21:24:54 -0000	1.242
+++ sys/dev/usb/uvideo.c	25 Feb 2025 17:45:14 -0000
@@ -2426,7 +2426,12 @@ uvideo_mmap_queue(struct uvideo_softc *s
 	sc->sc_mmap[i].v4l2_buf.bytesused = len;
 
 	/* timestamp it */
-	getmicrotime(&sc->sc_mmap[i].v4l2_buf.timestamp);
+	getmicrouptime(&sc->sc_mmap[i].v4l2_buf.timestamp);
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TIMESTAMP_MASK;
+	sc->sc_mmap[i].v4l2_buf.flags |= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK;
+	sc->sc_mmap[i].v4l2_buf.flags |= V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
+	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_TIMECODE;
 
 	/* forward error bit */
 	sc->sc_mmap[i].v4l2_buf.flags &= ~V4L2_BUF_FLAG_ERROR;