diff mbox series

[v8,1/6] media: uvcvideo: Fix negative modulus calculation

Message ID 20220920-resend-hwtimestamp-v8-1-0edaca2e2ab3@chromium.org
State New
Headers
Series uvcvideo: Fixes for hw timestamping |

Commit Message

Ricardo Ribalda March 15, 2023, 12:35 p.m. UTC 
  If head is 0, last will be addressing the index 0 instead of clock->size
-1. Luckily clock->head is unsiged, otherwise it would be addressing
0xffffffff.

Nontheless, this is not the intented behaviour and should be fixed.

Fixes: 66847ef013cc ("[media] uvcvideo: Add UVC timestamps support")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index d4b023d4de7c..4ff4ab4471fe 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -732,7 +732,7 @@  void uvc_video_clock_update(struct uvc_streaming *stream,
 		goto done;
 
 	first = &clock->samples[clock->head];
-	last = &clock->samples[(clock->head - 1) % clock->size];
+	last = &clock->samples[(clock->head - 1 + clock->size) % clock->size];
 
 	/* First step, PTS to SOF conversion. */
 	delta_stc = buf->pts - (1UL << 31);