On Wed, 6 Mar 2013, Albert Wang wrote:
[snip]
> >> + if (cam->frame_state.usebufs == 0)
> >> + cam->frame_state.usebufs++;
> >> + else {
> >> + set_bit(CF_SINGLE_BUFFER, &cam->flags);
> >> + cam->frame_state.singles++;
> >> + if (cam->frame_state.usebufs < 2)
> >> + cam->frame_state.usebufs++;
> >
> >What is this .usebufs actually supposed to do? AFAICS, it is only used to
> >decide, whether it should be changed, I don't see it having any effect on
> >anything else?
> >
> Actually, we use .usebufs to decide if will enter single buffer mode.
> Only usebufs == 2 can enter single buffer mode.
> But when init it:
> If CCIC use Two Buffers mode, init usebufs == 1
> If CCIC use Three Buffers mode, init usebufs == 0
> That means when CCIC use Two Buffers mode, once buffer used out, CCIC will enter single buffer mode soon
> But when CCIC use Two Buffers mode, we can have 1 frame time to wait for
> new buffer and needn't enter single buffer mode.
> If we still can't get new buffer after 1 frame, then CCIC has to enter single buffer mode.
> But if we are lucky enough and get new buffer when next frame come, then
> we can still run in normal mode.
Thanks for the explanation. Could you please tell me where in the code
this .usebufs field is used as you describe?
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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