On Mon, 23 Mar 2015, Marc Joliet wrote:

> > - If I leave the drive unplugged during boot and plug it in without manually
> >   loading any modules, nothing happens.  That is, the kernel does not log
> >   anything about the device being attached, and neither the uas nor the
> >   usb-storage modules are loaded (I did see something happen with usbmon, 
> > but I
> >   accidentally clobbered the file, so I'll have to recapture that).
> 
> Here it is, the entirety of what usbmon captures in this case:
> 
> d24a0240 0.209658 C Ii:2:003:3 0:2 15 =
>     20010100 00000000 00000000 000000
>        . . .  . . . .  . . . .  . . .
> d24a0240 0.209727 S Ii:2:003:3 -:2 32 <
> b752f480 7.241479 S Ci:3:001:0 s a3 00 0000 0001 0004 4 <
> b752f480 7.241507 C Ci:3:001:0 0 4 =
>     00010000
> b752f480 7.241516 S Ci:3:001:0 s a3 00 0000 0002 0004 4 <
> b752f480 7.241525 C Ci:3:001:0 0 4 =
>     00010100
> b752f480 7.241532 S Co:3:001:0 s 23 01 0010 0002 0000 0
> b752f480 7.241543 C Co:3:001:0 0 0
> dd776540 7.341741 S Ii:3:001:1 -:2048 4 <
> dd776540 7.341768 C Ii:3:001:1 -2:2048 0

This indicates that the connection existed only for a very brief period 
of time (a lot less than one second) and then the device disconnected.

> I also forgot to mention: unplugging the drive and plugging it back in works 
> as
> in the original problem description.  So again: the first connect fails to do
> anything, but the second works.

This certainly sounds like a bug in the drive's USB adapter.  
Evidently it is programmed to behave differently the first time it is 
plugged in.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to