On Thu, May 11, 2000 at 09:37:03PM +0100, Tim Waugh wrote:
> On Thu, May 11, 2000 at 02:15:52PM -0400, Derek Bouius wrote:
>
> > I really need read DMA for my device.
>
> See the archives of this list for why PIO reading hasn't been done yet
> (I have the fix but it isn't properly integrated yet). As for DMA, I
> think it just hasn't been tested much.
I did some pio-reading tests and I could read a single frame but the
port was not switched back correctly, at least not for my device (a
CPiA based webcam). In any case, the block-read interface is not
suitable for my purpose. A webcam delivers a stream of indefinite
length (due to compression). The end-of-stream is a data pattern in the
stream. The current read-functions do ieee-mode switching after reading
blocks which must not happen for the webcam. So I see no way to
implement streaming read with the current interface. I will try to show
some working code that implements what I need.
AFAIK, there is no dma-read code in the current 2.3.x-kernels.
-Peter
-- Even the thought that a ship was waiting to take him back to Earth did not wipe out the sense of loss he felt at that moment. ------------------------------- Email: Peter_Pregler@email.com
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