I am trying to debug a USB device / driver problem. My system has a 5 port
hub attached to a root port of my PC. Attached to this hub are 4 devices
and another hub. The second / cascaded hub also has a device attached to
it.
My problem is this: occasionally, every couple of weeks, all the devices
attached to the first hub is seen as being removed then reattached,
including the second hub and its device. We see this by requesting PnP
device change notifications and logging the events as they occur.
Note: The 1st hub does not get removed/reattached.
Note: One of the devices attached to the 1st hub does not get reattached.
Questions:
What could cause all devices on a hub to be re-enumerated?
Is there a USB stack function call that would cause this?
Could a hardware fault of a device attached to the 1st hub cause this?
Anyone know of a method to pinpoint the cause of this problem
Harmon
Beware of electric static discharge (ESD), esp with cables which are longer then the max specified length (I think it is 2m for a usb 1.1 calbe). Hook up a CATC or other bus snooping device and see if there are any abnormal packets on the wire.
d
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Harmon, Larry (CT)
Sent: Monday, March 28, 2005 12:35 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] usb 1.1 device removal / arrival
I am trying to debug a USB device / driver problem.? My system has a 5 port hub attached to a root port of my PC.? Attached to this hub are 4 devices and another hub.? The second / cascaded hub also has a device attached to it.
My problem is this:? occasionally, every couple of weeks, all the devices attached to the first hub is seen as being removed then reattached, including the second hub and its device.? We see this by requesting PnP device change notifications and logging the events as they occur.
Note:? The 1st hub does not get removed/reattached.
Note:? One of the devices attached to the 1st hub does not get reattached.
Questions:
??? What could cause all devices on a hub to be re-enumerated?
Is there a USB stack function call that would cause this?
Could a hardware fault of a device attached to the 1st hub cause this?
Anyone know of a method to pinpoint the cause of this problem
Harmon
???
Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256
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— “Harmon, Larry (CT)” wrote:
>
> I am trying to debug a USB device / driver problem.
> My system has a 5 port
> hub attached to a root port of my PC. Attached to
> this hub are 4 devices
> and another hub. The second / cascaded hub also has
> a device attached to
> it.
>
> My problem is this: occasionally, every couple of
> weeks, all the devices
> attached to the first hub is seen as being removed
> then reattached,
> including the second hub and its device. We see
> this by requesting PnP
> device change notifications and logging the events
> as they occur.
>
> Note: The 1st hub does not get removed/reattached.
> Note: One of the devices attached to the 1st hub
> does not get reattached.
>
> Questions:
>
> What could cause all devices on a hub to be
> re-enumerated?
> Is there a USB stack function call that would cause
> this?
> Could a hardware fault of a device attached to the
> 1st hub cause this?
> Anyone know of a method to pinpoint the cause of
> this problem
>
> Harmon
>
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as:
> xxxxx@yahoo.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
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