Ubuntu
linux-source-2.6.22 package

  1. Bug #88746 (ehci-hcd)
  2. Comment #523

Comment 523 for bug 88746

Revision history for this message
Arnaud Quette (aquette) wrote : Re: [Bug 88746] Re: ehci_hcd module causes I/O errors in USB 2.0 devices

2009/5/15 halfmanhalfbug

> I have this exact problem with a particular SATA external hard-drive using
> kernel 2.6.24 (Hardy) and 2.6.27 (Jaunty). My observation is that plugging
> in the device with only one USB connection results in the problem (infinite
> resets) but plugging in the device with 2 connections (1 data+power and 1
> power only) results in correct polling and mounting.
> I am wondering if the USB 2.0 driver is supposed to sense and allocate
> power (or more precisely current)? Incorrect powering would explain why the
> problem is only seen with certain hardware combinations and is especially
> seen with USB hubs, which split power.
>

this is not software related, but hardware related here.
these kind of external devs need more power than a single USB connection can
provide.
I've personnaly an external cdrom drive like that.
an "idiot proof" is to run the same dev on another platform. result
guaranteed ;-)

Arnaud