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From: Armageddon on 1 May 2008 20:53
I have a full speed USB device that I'm developing that uses usbser.sys.
I found that if I connect the device directly to my Dell laptop everything
works find. If I connect the device through a high speed USB 2.0 hub
everything is very flaky. I see hangs when opening the com port, Windows
lockups, and other wierd falures.

I found a workaround. If I disabled the enhanced USB controller in
device manager to force the hub to use full speed everything is rock solid.
So this makes me think the problem is either a bug in Windows or a bug with
the Intel chipset in my Dell Inspiron laptop.

1. Is this a known bug in usbser.sys or Windows?
2. What do I need to do to report the problem?

My operating system is Vista SP1.
From: chris.aseltine on 1 May 2008 22:13
On May 1, 7:53 pm, Armageddon <Armaged...(a)discussions.microsoft.com>
wrote:

> I found a workaround. If I disabled the enhanced USB controller in
> device manager to force the hub to use full speed everything is rock solid.
> So this makes me think the problem is either a bug in Windows or a bug with
> the Intel chipset in my Dell Inspiron laptop.

I highly doubt this is an issue with usbser.sys as most class drivers
don't care, or even know, about whether the underlying device is USB
1.1, USB 2.0, or even a real physical device at all. I wouldn't blame
Windows or your laptop -- I'd say 90% chance your device is buggy.
From: Armageddon on 1 May 2008 22:29


"chris.aseltine(a)gmail.com" wrote:

> On May 1, 7:53 pm, Armageddon <Armaged...(a)discussions.microsoft.com>
> wrote:
>
> > I found a workaround. If I disabled the enhanced USB controller in
> > device manager to force the hub to use full speed everything is rock solid.
> > So this makes me think the problem is either a bug in Windows or a bug with
> > the Intel chipset in my Dell Inspiron laptop.
>
> I highly doubt this is an issue with usbser.sys as most class drivers
> don't care, or even know, about whether the underlying device is USB
> 1.1, USB 2.0, or even a real physical device at all. I wouldn't blame
> Windows or your laptop -- I'd say 90% chance your device is buggy.
>

And Windows is bug free?

The firmware on the device also doesn't care if a hub is used or not. The
device is a full speed device so I'm confused how having a high speed link
between the hub and the PC can make a difference as far as the device is
concerned. Doesn't the link from the hub to the device simply look like a
plain full speed link?

I'm also confused why Windows malfunctions. It's not just that the device
doesn't work. Isn't the driver stack different if a hub is used? Perhaps
it's some kind of wierd interaction between device drivers.
From: chris.aseltine on 2 May 2008 11:06
On May 1, 9:29 pm, Armageddon <Armaged...(a)discussions.microsoft.com>
wrote:

> And Windows is bug free?

Did I say that?

> The firmware on the device also doesn't care if a hub is used or not. The
> device is a full speed device so I'm confused how having a high speed link
> between the hub and the PC can make a difference as far as the device is
> concerned. Doesn't the link from the hub to the device simply look like a
> plain full speed link?

Get a bus analyzer and compare traces between connecting it directly
and connecting it through a hub, and look for errors. If your device
is going wild on the wire, you could potentially bugcheck the machine,
but that's not really the host's fault (inasmuch as you're not going
to get a hotfix to work around a device's buggy behavior).

> I'm also confused why Windows malfunctions. It's not just that the device
> doesn't work. Isn't the driver stack different if a hub is used? Perhaps
> it's some kind of wierd interaction between device drivers.

Assuming it's a 2.0 hub, then you'll be hitting the EHCI stack on the
host side, yes.
From: Pavel A. on 2 May 2008 10:19
"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)

--PA


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