Re: Guidance on USB Contoller listing in Device Manager, please


An USB host controller and an USB root hub is the same
hardware device. The host controller is the logical device
at the PCI bus side while the USB root hub is the logical
USB side which provides USB ports. It's all hardware
which needs software (drivers) to be used.

An USB2 controller has two logical 'incarnations', one for
USB2 and some for USB1. It depends on the attached device
which incarnation is used. The USB1 incarnations are usually
splitted, so each incarnation ususally has two ports.
Microsoft UVCView shows it:
http://www.microsoft.com/whdc/device/stream/vidcap/UVCView.mspx
With this tool you will see that the number of USB2 and USB1 ports
is equal because they are identical physical ports.


Uwe



x-eyed-bear wrote:
I'm one of the thousands of users who has the dreaded 'USB Device not recognized' error. I don't want to burden this forum (yet) but asking for help on that one. I'm trying to solve it myself by better understanding how USB devices are handled by Windows XP (SP2, that is). I need some guidance on understanding the meaning and significance of the 'USB Controller' section of the Device Manager window.

On my system (ASUS A8V motherboard with 6 out of a possible 8 USB ports installed) the listing shows:

'USB Root Hub' (4 times)
'VIA Universal Host Controller' (3 times)
'VIA USB Enhanced Host Controller' (once)

Loads of newbie Questions:
1. What is a Hub and what is a Root Hub? Are they hardware, microcode or software?
2. What is a USB port and how does it differ to a hub?
3. What is a Host Controller? Is it hardware, microcode or software?
4. I am right in assuming an Enhanced Host Controller is one which provides USB 2.0 support, the others being USB 1.1 only?
5. Why does the output from SiSoft Sandra show no devices attached to any of the 6 ports on the Enhanced Host Controller, but does show the expected devices connected to either Port 1 or Port 2 on one of the three Universal Host Controllers?
6. Why have I got 3 of these host controllers and not just 1 like the Enhanced Host Controller?
7. What is 'Enumeration' and why would a device connected to a USB port fail this process?
8. Is the driver that is listed in the properties for a Hub or Host Controller part of Windows XP, or a specific piece of software supplied with the device?
9. Why do some device have no such driver (for example the Nikon D80 DSLR camera which Windows XP will not recognise - but only on this computer)?


Finally, why do so many people report a 'USB Device Not recognized' error, across such a wide range of systems and devices, across so many years, without a definitive solution being developed by the industry? Microsoft's absence from the this scene is a disgrace. The cost to users must run into 10's of thousands of man hours by now. There are thousands of pages of guidance on the internet which range from the incredible to the insightful - many of them contradicting others. None of them have solved my specific example (but I've only been trying to solve this for 2 weeks ....). If we had this sort of problem with our cars, telephones, TVs, etc, it would have been the subject of incisive media analysis. Why do we let the computer industry get away with this situation? Nikon's technical support response to the problem could form the script for a Broadway comedy; it includes re-installing XP. Who is going to pay for that?
.

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