Reasons for USB Device Reinstall

What are the reasons, other than the USB serial number, that would cause a
USB device to be reinstalled when moved to a new USB port? We are in the
process of developing a USB device and even though we are specifying a serial
number, the Add New Hardware wizard pops up whenever the device is moved to a
new port. We are specifying a string descriptor index in the device
descriptor and the value of the serial number is the Unicode string
â??0123456789â??. This is a temporary value for development purposes, when the
device goes into production, each will have its own serial number. Even so,
shouldnâ??t this value be sufficient to qualify as a valid USB serial number?

Mike

Doron
Sun Feb 13 18:28:07 CST 2005

does the device path ID (ie usb\vid_xxx&pid_yyyy\<instance id>) contain your
serial number somewhere in the <instance id>? if not, i would assume that
the serial number is not wired up correctly (in the config descriptor i
think) or the OS cannot retrieve it.

d

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"Mike Yoke" <MikeYoke@discussions.microsoft.com> wrote in message
news:572D9674-617E-4A0B-8381-1A1051399E92@microsoft.com...
> What are the reasons, other than the USB serial number, that would cause a
> USB device to be reinstalled when moved to a new USB port? We are in the
> process of developing a USB device and even though we are specifying a
> serial
> number, the Add New Hardware wizard pops up whenever the device is moved
> to a
> new port. We are specifying a string descriptor index in the device
> descriptor and the value of the serial number is the Unicode string
> "0123456789". This is a temporary value for development purposes, when
> the
> device goes into production, each will have its own serial number. Even
> so,
> shouldn't this value be sufficient to qualify as a valid USB serial
> number?
>
> Mike
>
>

Robert
Mon Feb 14 01:51:56 CST 2005

Doron Holan [MS] wrote:

> does the device path ID (ie usb\vid_xxx&pid_yyyy\<instance id>) contain your
> serial number somewhere in the <instance id>? if not, i would assume that
> the serial number is not wired up correctly (in the config descriptor i
> think) or the OS cannot retrieve it.

The common firmware bug for that would be not to send an empty packet
for strings which have a length which is evenly divisible by 8.

Maxim
Tue Feb 15 07:50:59 CST 2005

> new port. We are specifying a string descriptor index in the device
> descriptor and the value of the serial number is the Unicode string
> "0123456789". This is a temporary value for development purposes, when the

Note: insert 2 devices and the OS will crash. Your production environment MUST
provide uniqueness of these numbers.

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Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
maxim@storagecraft.com
http://www.storagecraft.com