Re: OvlK_Wait() fails for iso EP poll rate >1ms

Thanks Travis.

Then I'll bury this issue. Pity, really. That poor scheduler doesn't
need to do all this work.

It works, but I need to tell users they must use a powerfull computer
to pull it off.


Have a good weekend!

Best,
Børge


On Fri, Aug 22, 2014 at 4:45 PM, Travis <[email protected]> wrote:
> Greetings,
>
> This is a windows limitation.  For high speed ISO, bInterval can be only
> 1,2,3, or 4.
>   http://msdn.microsoft.com/en-us/library/windows/hardware/hh406225%28v=vs.85%29.aspx
>
> Back in early beta I standardize on "INT, UINT, PINT, PUINT" for 32bit
> types.  Understand that long's are also 32 bit types in C/C++.
> Microsoft has a habit of making a mess with all of these.
>
> Regards,
> Travis
>
> On 8/22/2014 6:47 AM, Børge Strand-Bergesen wrote:
>> Hi guys,
>>
>> I'm working on a USB ASIO driver based on libusbK. It uses an
>> isochronous IN endpont for a feedback from the Device. Descriptor dump
>> is attached.
>>
>> The ASIO driver fails when the IN endpoint's poll rate becomes >1ms.
>> (See w5.txt line 220.) Rapid polling isn't needed in the application,
>> and I'd like to make it slower.
>>
>> Values of 4 and below work as expected in libusbK and mimic what I see
>> in Linux. 4 gives 1ms polling rate, 3->1/2ms, 2->1/4ms etc. But on
>> Linux I also have 5->2ms, 6->4ms, 7->8ms, 8->16ms. (Testing on OS X
>> roughly tracks what I see on Linux, but with fewer transitions. There
>> may be bugs in the descriptors which cause libusbK and OS X to
>> misunderstand them in different ways, where Linux seems to be OK.)
>>
>> What seems to happen is a failure in OvlK_Wait(). When called,
>> GetLastErrorInternal(); returns 00000057h.
>>
>> The calling code is line 138 of:
>> https://github.com/nikkov/Win-Widget/blob/experimental/uaclib/UsbDevice.h
>>
>> I use the latest libusbK 3.0.7.0 which I downloaded, linked to and
>> installed today. The built .dll is a 32-bit application. My system is
>> Win7-64.
>>
>> One thing I notice is that OvlK_Wait() parameter TransferredLength is
>> now PUINT. In the ASIO driver code it was PULONG for a while, but I
>> believe I have fixed that in all of the code now.
>>
>> I hope you can help me out with this issue. I hope device performance
>> will be better on weaker computers with slower polling.
>>
>> Let me know if you need more details about my system.
>>
>>
>> Thanks,
>> Børge
>>
>>
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