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[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 <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Laurent Pinchart 2012-01-15 13:53:45 -03:00 committed by Mauro Carvalho Chehab
parent fda27874de
commit 8e57dec045
1 changed files with 9 additions and 5 deletions
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14
drivers/media/video/uvc/uvc_video.c
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@ -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