Re: [linux-usb-devel] 2.6: USB disk unusable level of data corruption

[David Brownell <david-b@pacbell.net>]

On Friday 04 February 2005 4:16 am, Rusty Russell wrote:
> 
> Is USB/SCSI just terminally broken under 2.6?  

I don't think so, but there are problems that appear in some
hardware configs and not others.  Many folk report no problems;
a (very) few report nothing but.

If you've verified this on 2.6.10, then you certainly have
have the ehci-hcd (re)queueing race fix that has made a big
difference for some folk.  I don't know of any other issues
in that driver that could explain usb-storage problems.

What hardware config do you have?

  - Whose EHCI controller and revision?  I've never had
    good luck with VIA VT6202.  ("lspci -v".)

  - Whose USB storage adapter?  ("lsusb -v", or in this
    case the /proc/bus/usb/devices entry would be ok.)
    GeneSys adapters have been the most problematic,
    but they're hardly the only ones with quirks.

Thing is, that driver stack isn't especially thin:  SCSI isn't
the top, and it's got usb-storage, usbcore, and a USB HCD under
it.  That makes it harder to track down root causes, even when
there is just a single one and it's in those drivers (rather
than being hardware misbehavior).

- Dave