Re: usb device problem

[Mark Lord <lkml@rtr.ca>]

Mark Lord wrote:
> Jiri Slaby wrote:
>> Mark Lord napsal(a):
>>> Jiri Slaby wrote:
..
>>>> ---
>>>> sd 10:0:0:0: SCSI error: return code = 0x10070000
>>>> end_request: I/O error, dev sdb, sector 1575
..
> The 0x1007000 is broken down as:
> 
> 07 == "host byte"   = DID_ERROR = "internal error"
> 10 == "driver byte" = SUGGEST_RETRY
..
>>> I have a patch to fix this behaviour (in sd.c), but it has not yet
>>> been decided whether to go upstream with it or not.
>>
>> Could you post me a copy, please?
> 
> Probably tomorrow.  I haven't ported it forward yet (from a much older 
> kernel).
> But I don't think it will help here now, as these errors
> don't really look like bad media -- gotta look inside the usb-storage 

Mmm.. okay, a quick glance at the USB storage code revealed one instance:

        /* Did we transfer less than the minimum amount required? */
        if (srb->result == SAM_STAT_GOOD &&
                        srb->request_bufflen - srb->resid < srb->underflow)
                srb->result = (DID_ERROR << 16) | (SUGGEST_RETRY << 24);

        return;

So I suppose this *could* be the driver thinking it had a bad sector,
but it really looks like it's guessing.  The code also appears to be
instrumented for some kind of USB tracing.. If you can figure out how
to turn that on, then the trace will probably tell us what is really
going on there. 

Look for a file called "usbmon.txt" in the Documentation/usb/ subdir
of your kernel source tree.  It describes how to do the tracing.

I'll also CC: you when I send out the SCSI error-recovery draft patch.

Cheers