thanks Alan for responding (again !)
2005/9/1, Alan Stern <[EMAIL PROTECTED]>:
> On Thu, 1 Sep 2005, Franck wrote:
>
> > Hi,
> >
> > I'm trying to write a host controller driver for a Arc hardware. I
> > need to know how nak pid should be handled ? Hardware can
> > automatically manage them, that means it automatically retry the
> > naked transaction. But since setup packet must not be "NAKed" or hub
> > endpoint #1 returns nak pid when no events happen on its port, I don't
> > think I can use this feature.
>
> Sure you can. The hardware should be smart enough to recognize that a NAK
> response to a SETUP packet is an error, so it won't retry the transaction.
Not sure the hardware is clever enough. If the hardware quality is the
same level as the datasheet's one then it wont't be smart enough !
> And NAK response to an interrupt transfer definitely _should_ be retried,
> at the next interrupt period.
ok so I definetly can't use this feature for interrupt polling and
isoc transfer.
>
> > But if I do it manually, what should I
> > do when receiving a NAK ? Should I retry the transaction forever ?
>
> Yes. Until someone unlinks the URB.
but if the NAKed transaction lasts more than a frame ?
Thanks
--
Franck
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