douts on usb 2.0

NTDEV
1

Hai;

In usb 2.0 maximum support devices is 127 + rootHub. If the user adds
more than 127 devices. what will happen.Is it possible to add any number of
devices as per user need.

Any one know the answer please reply me.

Thanks&Regards;
B.sudhakar.

2

The limit is a total of 127 devices and 5 hub levels deep. If you
exceed the 5 hub limit, it won’t enumerate. IIRC, since device addresss
are a byte (with the top bit used for something else), if you exceed 127
devices, the devices are not addressable by the bus and won’t enumerate.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ganesh
Sent: Friday, September 10, 2004 4:35 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] douts on usb 2.0

Hai;

In usb 2.0 maximum support devices is 127 + rootHub. If the user
adds
more than 127 devices. what will happen.Is it possible to add any number
of
devices as per user need.

Any one know the answer please reply me.

Thanks&Regards;
B.sudhakar.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Since it is an 8-bit value for USB device addresses, it is a bus
limitation for 127 devices. If you try to exceed that, the USB stack
can’t configure the device without taking some other device off line
(which it won’t do).

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ganesh
Sent: Friday, September 10, 2004 4:35 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] douts on usb 2.0

Hai;

In usb 2.0 maximum support devices is 127 + rootHub. If the user
adds
more than 127 devices. what will happen.Is it possible to add any number
of
devices as per user need.

Any one know the answer please reply me.

Thanks&Regards;
B.sudhakar.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@nvidia.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

What if one to disable a device. Would the stack then let another one
take its place?

-p

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Mark Overby
Sent: Friday, September 10, 2004 10:37 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] douts on usb 2.0

Since it is an 8-bit value for USB device addresses, it is a
bus limitation for 127 devices. If you try to exceed that,
the USB stack can’t configure the device without taking some
other device off line (which it won’t do).

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ganesh
Sent: Friday, September 10, 2004 4:35 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] douts on usb 2.0

Hai;

In usb 2.0 maximum support devices is 127 + rootHub. If
the user adds more than 127 devices. what will happen.Is it
possible to add any number of devices as per user need.

Any one know the answer please reply me.

Thanks&Regards;
B.sudhakar.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@nvidia.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag
argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

5

I think if you reinserted the device, it would work.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Peter Wieland
Sent: Friday, September 10, 2004 10:50 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] douts on usb 2.0

What if one to disable a device. Would the stack then let another one
take its place?

-p

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Mark Overby
Sent: Friday, September 10, 2004 10:37 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] douts on usb 2.0

Since it is an 8-bit value for USB device addresses, it is a
bus limitation for 127 devices. If you try to exceed that,
the USB stack can’t configure the device without taking some
other device off line (which it won’t do).

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ganesh
Sent: Friday, September 10, 2004 4:35 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] douts on usb 2.0

Hai;

In usb 2.0 maximum support devices is 127 + rootHub. If
the user adds more than 127 devices. what will happen.Is it
possible to add any number of devices as per user need.

Any one know the answer please reply me.

Thanks&Regards;
B.sudhakar.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@nvidia.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag
argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag argument:
‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com