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From: Ben Voigt [C++ MVP] on 8 May 2008 12:42
Pavel A. wrote:
> "Armageddon" <Armageddon(a)discussions.microsoft.com> wrote in message
> news:D80B0827-3D9C-41E5-A470-036D4D6BA4EE(a)microsoft.com...
>
>> Doesn't the link from the hub to the device simply look like a
>> plain full speed link?
>
> No, the physical signaling is different in high speed mode (besides
> of the obvious timing differences)

The link from the full-speed device to the hub is the same as from
full-speed device to root port. The hub has to manage translating
everything to high-speed.

>
> --PA


From: Ben Voigt [C++ MVP] on 8 May 2008 12:47
> Is the problem here that usbser.sys just isn't very supported by
> Microsoft because it isn't high priority. Has anybody else tried
> connecting a full speed usbser.sys device to a host via a high speed
> hub? Unforntinatly, their arn't very many usbser devices and I don't
> own any to try.

We've seen various problems with different devices when connected through a
high-speed hub.

We're have some FTDI serial chips right now that don't use the usbser.sys
but will be evaling the Microchip PIC-based USB chips because the FTDI
drivers are plenty buggy.

You might additionally try putting a full-speed hub upstream of the
high-speed hub, and see what happens there. Probably the same as if you
forced the root port into full-speed by disabling EHCI.


From: Ben Voigt [C++ MVP] on 8 May 2008 12:48
chris.aseltine(a)gmail.com wrote:
> On May 2, 11:56 am, Armageddon <Armaged...(a)discussions.microsoft.com>
> wrote:
>
>> Is the problem here that usbser.sys just isn't very supported by
>> Microsoft because it isn't high priority.
>
> Look, no. Why are you blaming usbser.sys without any evidence? Why
> do you think it's "not very supported" or "not a high priority"?
>
>> Has anybody else tried connecting a full speed usbser.sys device to
>> a host via a high speed hub?
>
> Yes. I've personally done this hundreds, if not thousands of times
> with no issues.

Which chip is used for the device-side USB interface?


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