Driver Reinstall When Switching USB Ports

Piyono

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One of those things that I've always noticed but never researched is Windows' tendency to reinstall a driver when a USB device is unplugged from one port and plugged into a different port.

It just happened today with an M-Audio Fast Track Pro which I've been using for a couple of weeks. I swapped it to a different port and XP got all excited. "New hardware! Awesome! I know what to do!"

Why does this happen?

]-[
 

Chewy509

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Most onboard USB ports have individual controller IDs. (Look in device manager, and you'll see a huge group of USB controllers).

Since (according to Windows) you are connecting a device to a "new"/different controller, it has to redo the drivers...
 

Piyono

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Yeah, but I figured that once a device is installed it's, you know, installed...

Besides, this happens even between two ports on the same controller.
 

Will Rickards

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I read about this somewhere ... maybe wikipedia? That some devices identify themselves uniquely and some do not. But I can't seem to locate the source of my information.
 

sechs

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\roothub0\device
is different than
\roothub1\device

Therefore, it has to install new drivers on the new port. It might be nice if it did this silently (ever seen a driver install for an ATA drive?).
 

mubs

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Not true. This happens even if the device is installed to the same exact port. Just happened with my APC UPS which got unplugged; when I plugged it back in, XP did the same "new hw discovered" shit.
 

Bozo

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The USB port has to unload the driver when a device is removed. It doesn't know what is going to be installed there next. Hard drive, memory stick, printer? Each would have its own driver.

Bozo :joker:
 

sechs

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Not true. This happens even if the device is installed to the same exact port. Just happened with my APC UPS which got unplugged; when I plugged it back in, XP did the same "new hw discovered" shit.
Same thing happens with a PCI card. Should one expect USB to be different?
 
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