Hi Steve,
Thanks for your reply.
frameStart = fDevice->GetBus()->GetFrameNumber();
pipe->Read(..., frameStart, ...);
I issue one isoch read request by the way list upper, and this way works
well.
But how to queued in time serveral isoch read in time to usb bus?
Is there any example?
Thanks.
----- Original Message -----
From: "Steve Sisak" <email@hidden>
To: "Gordon" <email@hidden>; <email@hidden>
Sent: Monday, October 17, 2005 6:58 PM
Subject: Re: How to Queue isoch read request
> At 5:20 PM +0800 10/17/05, Gordon wrote:
>>
>>frameStart += 100;
>>for (int i = 0; i <4; i++)
>>{
>> pipe->Read( frameStart, ... );
>> frameStart += MAX_FRAME;
>>}
>>
>> But I can only get one error code: kIOReturnIsoTooNew
>>means that The isochronous I/O request is too early.So If
>>my way to queue isoch read request is wrong,what is the correct
>>way? Is there some sample like this for me?
>
> Hi Gordon,
>
> Either you didn't fill out the packet numbers in your buffers correctly or
> your request didn't get queued in time to go out the bus (but I thought
> that returned kIOReturnIsoTooOld -- it was kUSBNotSent2Err on Mac OS 9)
>
> What I do when starting up an isochronous stream for reading it just queue
> reads starting and the current frame number and just respect to receive
> kIOReturnIsoTooOld packet errors until I catch up to the current frame
> number on the USB bus.
>
> This has the advantage of starting as quickly as possible and always
> working, regardless of how long it takes the initial request to be queued.
>
> HTH,
>
> -Steve
> --
> _________________________________________________________________________
> Steve Sisak, CTO email@hidden
> IOXperts, Inc. +1 617 876-2572
>
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