High bandwidth USB 2.0 Endpoints

All,

While doing some research on the web I’ve seen some info stating that, for
Windows XP, high bandwidth transfers are only supported for iso endpoints.

Are there any versions of the Windows OS + service pack that extends high
bandwidth transfers to interrupt in/out endpoints?
Does any one know of a 3rd party controller/driver that supports high
bandwidth transfers for interrupt in/out endpoints?

Thanks in advance.

Hi Al,
Hi Jimmy,

my experince is that high bandwidth transfers (HBW) are not supported,
but maybee I’m missing something. I tried to implement it some time ago,
but without any success.
At that time Windows 7 was not available yet, so I can not tell you that
OS version.

I’m still interested in any news about the HBW mode, so please let us know.

/Uwe

Jimmy James schrieb:

All,

While doing some research on the web I’ve seen some info stating that, for
Windows XP, high bandwidth transfers are only supported for iso endpoints.

Are there any versions of the Windows OS + service pack that extends high
bandwidth transfers to interrupt in/out endpoints?
Does any one know of a 3rd party controller/driver that supports high
bandwidth transfers for interrupt in/out endpoints?

Thanks in advance.

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On Fri, Jul 24, 2009 at 10:21:14AM +0200, uwekirst wrote:

my experince is that high bandwidth transfers (HBW) are not supported,
but maybee I’m missing something. I tried to implement it some time ago,
but without any success.

We should be clear that we are talking only about interrupt endpoints
here. High-bandwidth isochronous endpoints work just fine, and have
done so all along.

I’ve never tried a high-bandwidth interrupt endpoint, so I don’t have
direct experience, although this is the first time I’ve ever seen an
implication that they aren’t supported.

Tim Roberts, xxxxx@probo.com
Providenza & Boeklheide, Inc.

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Hi Tim,

here is someone else reporting that HBW interrupt transfers are not working:

http://www.tech-archive.net/Archive/Development/microsoft.public.development.device.drivers/2004-10/1488.html

thanks,
/Uwe

xxxxx@probo.com schrieb:

I’ve never tried a high-bandwidth interrupt endpoint, so I don’t have
direct experience, although this is the first time I’ve ever seen an
implication that they aren’t supported.

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I’ve actually seen this. Jan Axelson’s book also says that high bandwidth
transfers are not supported for interrupt endpoints on WinXP. What makes me
skeptical though is that this information is all several years old and I
wonder if this issue has been addressed in a service pack or new version of
the OS. Can anyone confirm or deny?

“uwekirst” wrote in message news:xxxxx@ntdev…
> Hi Tim,
>
> here is someone else reporting that HBW interrupt transfers are not
> working:
>
> http://www.tech-archive.net/Archive/Development/microsoft.public.development.device.drivers/2004-10/1488.html
>
> thanks,
> /Uwe
>
> xxxxx@probo.com schrieb:
>> I’ve never tried a high-bandwidth interrupt endpoint, so I don’t have
>> direct experience, although this is the first time I’ve ever seen an
>> implication that they aren’t supported.
>>
>
>
> Email secured by Check Point at OSR.COM
>

In the Windows 7 version of USBEHCI.SYS I cannot find any code which ever sets the EHCI Queue Head Endpoint Capabilities DWORD2 bits 31:30 High-Bandwidth Pipe Multiplier field for a high-speed Interrupt endpoint to a value other than 1. (See Table 3-20 in the EHCI specification).

Based on that it would appear that high bandwidth (i.e. more than one transaction per endpoint per micro-frame) Interrupt endpoints are not supported in Windows 7, nor in any previous versions.

-Glen