USB root hubs

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Paul D.Smith

Background. My Dell PC uses the Intel 82801FB chipset which has 4 USB1.1
and a single USB2.0 ports. I'm not convinced that of the 8 USB sockets
available on my PC, they're really all USB2.0 as claimed by Dell.

So, looking at the Device Manager on XP I see the 5 USB ports, one enhanced
and the others base. I also see 5 root hubs - but what does this mean? I
also see the mouse plugged into on root hub, the keyboard into a second and
my monitor's hub into a third - what does this mean?

I "think" I get one root hub per (chipset) USB port but how can I match hub
to USB 1.1 or 2.0 driver?
I "think" the root hubs are telling me that some of the exposed USB sockets
are 1.1 and some are 2.0. But how do I tell?

Thanks for helping me make sense out of this all!
Paul DS.
 
The USB enhanced driver loading indicates at least one is 2.0 capable,
that's all. More MAY be USB 2.0 capable. Nothing in default XP can detect
if a USB port is USB 2.0 capable.
 
Jonny,

According to the Intel 82801FB specs, 1 x USB2.0 and 4 x USB1.1 is correct.
But can I match the root hubs to the hardware (chipset) ports in any way?

Dell imply "1 x USB2.0 is connected to an 8-port hub, 4 x USB1.1 are not
exposed", which doesn't seem to match with my reading of the USB root hubs
IFF (and this is the core of my question) there is a one-to-one mapping of
root hubs to chipset ports.

Paul DS.
 
The root hubs and ports may not match up, as there could also be port connections on the board that
are not hooked to anything. Also there can be multiple ports per hub, I added a 2.0 card that shows
1 enhanced root hub for the 2.0 and 2- 1.1 root hubs for backwards compatibility. There are 5
physical ports to connect to. I use a program called USB Monitor to tell what each USB connection
is doing .
 
David,

How do you even know that the root hubs are 1.1 or 2.0? Not trying to be
difficult - I really don't see how you can do this.

Thanks,
Paul DS
 
Paul

An older PC that really does only have USB 1.1 ports will not show anything
in Device manage to do with Enhanced USB.. the only way to get USB 2.0 on
such a machine would be to add a USB 2.0 port PCI adapter card..

In the case of your machine, assuming that you have no USB 2.0 PCI adapter
card fitted, and your machine shows 'Enhanced USB' in Device Manager, then
as Dell have told you already, all USB ports are vers. 2.0.. the ports on
the front panel of the case are wired from your motherboard, and will be USB
2.0 also..

Device manager will only show the four ports on the back panel by default,
and as you connect a device to each one, it will show what device is
connected.. the front panel ports will not show at all until such time as a
device is connected..
 
Mike,

I'm afraid I really don't understand why the front and back ports should be
treated differently. To give you a specific example, what I have and see is
the following....

Hardware

- 82801FB chipset which Intel claims has 1 x USB2.0 and 4 x USB1.1
- 6 physical USB sockets on the rear of the PC
- 2 physical sockets on the front of the PC
- A USB mouse connected to a rear socket
- A USB keyboard connected to a rear socket
- An active USB hub connected to a rear socket

Software

- One enhanced USB driver
- Four standard USB drivers
- 5 USB root hubs
- 1 root hub shows a USB mouse + 1 spare port
- 1 root hub shows a USB keyboard + 1 spare port
- 1 root hub shows the generic hub + 7 spare port
- 1 Generic hub (the active external hub - confirmed by unplugging it).

So, 5 USB drivers and apparently 12 ports! Is it any wonder that I'm
confused? How does this all relate to real hardware and the way in which
Windows XP manages it?

Paul DS
 
Paul

It is the way that the system reports them.. don't worry about it. if Dell
say you have all USB 2.0 ports, then that is what you have..

The active USB hub you have connected to the back may not be USB 2.0.. when
you bought it, did the packaging suggest USB 2.0?.. and why do you need an
extra hub with 6 ports already available?..
 
Mike,

The reason this has all come about is that copying data to & from my USB pen
drive on this Dell seems to be very slow - about as slow as my machine at
home which I know only has USB1.1 ports. My pendrive supports USB2.0 and
seems much faster on other machines, which made me suspicious about this
particular Dell.

Since I write software for a living, I foolishly though it would be possible
to make sense of the USB devices that WinXP instantiates to tell me whether
I really have USB2.0 or not - it seems that short of "use the force Luke", I
can't!

Aside: The hub is actually the Dell LCD screen that came with the Dell - it
has a built in powered hub which is claimed to be USB2.0 compatible - I
suppose it's worth checking this though! Also, the front USB ports on many
Dells are also carefully recessed which means that any pendrives don't
engage properly which is another reaon for using the readily accessible
screen/hub :-).

Paul DS.
 
All 5 port connections are 2.0, but they need the 1.1 hub hardware on the card for backward
compatibility for 1.1 devices.
The easiest way to tell if your connection is actually 2.0 is to plug a device that you know is 2.0
(USB pen drive, MP3 player) into the port. Windows will show a USB icon in the system tray and a
popup will come out telling you that if you plug it into a 2.0 port it will operate at a higher
speed. If you get this popup then the connection point you are plugged into is only 1.1.
 
I'd go by the Intel specs which speaks of hardware capability. All the
drivers in the world won't make the USB 1.1 types any faster.

The Dell (XP) explanation is considering the hub as an expansion of one
hardware USB port. Not any devices connected to the hub.

Just move a USB 2.0 flash drive around on the USB connections (no use of
hub). This will cue you in what is what.
 
Use the Device Manager.
Attach a USB 2.0 device to the port you want to check.
Then select 'View devices by connection".
Find your device.
If it is connected to the Root hub of the Enhanced controller, the port is USB2.0 capable.

Note. In some rare cases (bad cable/connector) a 2.0 device on 2.0 port works in 1.1 mode.
If so, clean the USB connectors; throw away the broken cable and get a good one.

Regards,
--PA
 
Pavel,

That's the best tip I've received. I can now figure out the "chain" of
drivers etc.

Thanks,
Paul DS
 
....snip...

Information for all...

Assume you have N (N is even normally) USB ports. If they are all USB2.0
compatible then you will see...

- (N/2) standard USB1.1 device drivers
- 1 enhanced USB2.0 device drivers
- (N/2) root hubs, (USB1.1) each with 2 ports
- 1 root hub, (USB2.0) with N ports.

A little confusing to me but that's how it works!

BTW, someone suggested using the "View device by connection" option from
Device Manager to see the "chain of command" whch allows you to figure out
whether your pen-drive (say) is plugged into a USB2.0 or USB1.1 port. I'd
heartily recommend this.

Paul DS.
 
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