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Re: ReadPipeTO timeouts not working?

At 11:54 AM -0500 10/24/06, robert engels wrote:

What I have found is that during certain exchange sequences, ReadPipeTO with a timeout specified (45000ms) returns immediately with kIOReturnSuccess but a read size of 0.

How can this be? Could the printer be signaling a NAK, or some such thing, and ReadPipeTO is interpreting this as a valid read.

It could be returning a zero length packet, only a bus trace would tell you for sure. You might get some hints from the logging family at a high logging level.

A NAK should never cause a completion.

I've seen printers which do return zero length packets when they have nothing to say. Its a reasonable way of saving bus bandwidth.
--
Barry Twycross
email@hidden
---
USB, it's not a Dyslexic BUS. (Thanks to TC.)
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 >ReadPipeTO timeouts not working? (From: robert engels <email@hidden>)



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