From 8e57dec0454d8a3ba987d18b3ab19922c766d4bc Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 15 Jan 2012 13:53:45 -0300 Subject: [PATCH] [media] [FOR,v3.3] uvcvideo: Avoid division by 0 in timestamp calculation Use system timestamps if the timestamp can't be computed from the data sent by the device. Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/uvc/uvc_video.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c index c7e69b8f81c9..4a44f9a1bae0 100644 --- a/drivers/media/video/uvc/uvc_video.c +++ b/drivers/media/video/uvc/uvc_video.c @@ -611,9 +611,11 @@ void uvc_video_clock_update(struct uvc_streaming *stream, delta_stc = buf->pts - (1UL << 31); x1 = first->dev_stc - delta_stc; x2 = last->dev_stc - delta_stc; + if (x1 == x2) + goto done; + y1 = (first->dev_sof + 2048) << 16; y2 = (last->dev_sof + 2048) << 16; - if (y2 < y1) y2 += 2048 << 16; @@ -631,14 +633,16 @@ void uvc_video_clock_update(struct uvc_streaming *stream, x1, x2, y1, y2, clock->sof_offset); /* Second step, SOF to host clock conversion. */ - ts = timespec_sub(last->host_ts, first->host_ts); x1 = (uvc_video_clock_host_sof(first) + 2048) << 16; x2 = (uvc_video_clock_host_sof(last) + 2048) << 16; - y1 = NSEC_PER_SEC; - y2 = (ts.tv_sec + 1) * NSEC_PER_SEC + ts.tv_nsec; - if (x2 < x1) x2 += 2048 << 16; + if (x1 == x2) + goto done; + + ts = timespec_sub(last->host_ts, first->host_ts); + y1 = NSEC_PER_SEC; + y2 = (ts.tv_sec + 1) * NSEC_PER_SEC + ts.tv_nsec; /* Interpolated and host SOF timestamps can wrap around at slightly * different times. Handle this by adding or removing 2048 to or from -- 2.20.1