Messages in this thread | | | Date | Sat, 18 Apr 2009 11:50:51 +0800 | From | leiming <> | Subject | Re: 2.6.30-rc2-git2: Reported regressions from 2.6.29 |
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On Fri, 17 Apr 2009 19:55:29 -0700 (PDT) Linus Torvalds <torvalds@linux-foundation.org> wrote:
> @@ -742,7 +742,7 @@ static int uvc_alloc_urb_buffers(struct > > uvc_video_device *video, > > /* Buffers are already allocated, bail out. */ > > if (video->urb_size) > > - return 0; > > + return DIV_ROUND_UP(video->urb_size, psize); > > I don't think this is right. It should round _down_. > > It's supposed to return 'npackets', but if you pass it a different > packet size than it was passed originally, it can now return a
Now uvc only uses the previous allocated buffer in suspend/resume path, so the packet size doen't change in this path.
> potentially bigger number than the already allocated buffer, no?
If this case does exist, the URBs need to be updated and the patch is not enough.
> > So I think it should round down (ie use a regular divide). No?
Because the following fact:
uvc_alloc_urb_buffers() { ... video->urb_size = psize * npackets; ... }
so DIV_ROUND_UP still can work correctly.
Thanks!
-- Lei Ming
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