Re: v4l2 + select() + read()

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> select() will initiate a new frame capture as a side effect if there is
> no (good) data ready. Otherwise it will sleep forever.

So for a dumb interface select() would effectively be 'wait for a vblank'
and read non block would return one frame then -EWOULDBLOCK until the vblank ?

> > A related problem:  The API document allows drivers to refuse read()
> > calls with sizes smaller than a full frame ("a partial frame may be
> > [ ... ] impractical or inefficient to implement").  Which doesn't
> > make sense to me, assuming we require the drivers to support
> 
> Hmmm. Maybe you're right. Am I giving too much discretion to the driver
> writer?

I'd rather we allowed partial reads, but Im not sure how hard it impacts the
drivers which are DMA based - I guess this is one for folks like Gerd Knorr

Alan





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