I'm forwarding a message I got from someone who was testing the
usb-storage driver. They've been able to reproduce (reliably) a problem
we discussed a while back on this list -- that usbdevfs will race with
other drivers.
What this user is seeing is this: He makes his LS-120 drive work for an
extended period of time copying data. He then does 'cat
/proc/bus/usb/devices' -- ka blammo! The drive is basically dead -- it
needs to be disconnected and reconnected to get it back into a sane state.
I have no idea if the data on the disk is being corrupted, but my guess is
that it could easily be (if not actually is).
This is something we need to fix. I'm pretty sure that this type of
interaction is possible with other devices, too. But this is the first
actual report I've seen from an end-user. I'm sure there will be more.
When we first talked about this problem (IIRC), there were two basic
solutions that were proposed:
(o) usbdevfs should cache the data so it doesn't need to access the device
(o) a per-device (or per-interface?) lock which would start in the locked
state for compatibility
I personally think the first option is better -- after all, why do we
bother to 'claim' interfaces _and_ have a lock? Claiming an interface
should be good enough -- other drivers should simply respect that.
Comments? I think this should be on the high-priority TODO list.
Matt Dharm
--
Matthew Dharm Home: [EMAIL PROTECTED]
Senior Engineer, QCP Inc. Work: [EMAIL PROTECTED]
I say, what are all those naked people doing?
-- Big client to Stef
User Friendly, 12/14/1997
---------- Forwarded message ----------
Date: Fri, 5 May 2000 20:57:03 +0200 (CEST)
From: Sergio Gomez Bachiller <[EMAIL PROTECTED]>
To: Matthew Dharm <[EMAIL PROTECTED]>
Cc: Sergio Gomez Bachiller <[EMAIL PROTECTED]>
Subject: Re: Imation Superdisk LS-120 now work!
Sorry, Im forbidden the body in the last mail
Im using UFI and SC_8070 and both work in 2.3.99-pre7-2
but if when I am copying files if I run:
cat /proc/bus/usb/devices
the process hang up and i must unplug my LS120 unit
Can be it a bug?
Un saludo,
/----------------------------------------------------------------------\
|Sergio G�mez Bachiller, operador becario de la Universidad de C�rdoba |
| <mailto:[EMAIL PROTECTED]> <http://rabcee02.uco.es/~sergio> |
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