[fonosfera] powered usb hub

Matthijs Kooijman matthijs at stdin.nl
Thu Dec 17 10:08:47 UTC 2009


Hi Hans,

> Can you tell a little more about what we need to look for.
> Perhaps a sample with a good and one with a 'bad' hub?

Hmm, I just checked and didn't find anything in dmesg. I guess it was there
before because I had USB debugging enabled in my kernel then.

Anyway, it seems lsusb -v does show this in the bDeviceProtocl field:

matthijs at xanthe:~$ sudo lsusb -v |grep bDeviceProtocol.*TT
  bDeviceProtocol         2 TT per port
  bDeviceProtocol         2 TT per port
  bDeviceProtocol         1 Single TT

(Note that this means the value of the field is 2, which means "TT per port",
not that there are 2 TT's per port)

The iProduct field also makes a reference for my multi TT hub:
  iProduct                1 USB 2.0 Hub [MTT]


Some reference about TT's:
http://www.tomshardware.com/reviews/usb-technology,677-3.html

Gr.

Matthijs
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