On Fri, 5 Jan 2007, Pete Zaitcev wrote:
> On Fri, 5 Jan 2007 10:52:27 -0500 (EST), Alan Stern <[EMAIL PROTECTED]> wrote:
>
> > We are led to the following reasoning:
> >
> > CB and CBI can't pass the LUN value as a control parameter,
> > but only as part of the CDB.
> >
> > If scsi_level is 0 then the LUN value won't be passed in the CDB.
> >
> > Hence any device using CB or CBI with scsi_level == 0 _must_
> > be single-LUN.
> >
> > Pete, I imagine this will solve your problem better than your proposed
> > change.
>
> OK, the patch works, although the /proc/scsi/scs now looks like this:
>
> Host: scsi1 Channel: 00 Id: 00 Lun: 00
> Vendor: AMI Model: Virtual CDROM Rev: 1.00
> Type: CD-ROM ANSI SCSI revision: ffffffff
> Host: scsi2 Channel: 00 Id: 00 Lun: 00
> Vendor: AMI Model: Virtual Floppy Rev: 1.00
> Type: Direct-Access ANSI SCSI revision: ffffffff
That looks like a simple bug in
drivers/scsi/scsi_proc.c:proc_print_scsidevice(). It should be easily
fixable. Near the end of the routine, make this change:
- " SCSI revision: %02x", (sdev->scsi_level > 1) ?
- sdev->scsi_level - 1 : 1);
+ " SCSI revision: %02x",
sdev->scsi_level - (sdev->scsi_level > 1));
> > - sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;
> > + if (sdev->scsi_level > SCSI_2)
> > + sdev->scsi_level = sdev->sdev_target->scsi_level =
> > + SCSI_2;
>
> This looks a little ugly. Can we have this instead:
>
> if (sdev->scsi_level > SCSI_2) {
> sdev->scsi_level = SCSI_2;
> sdev->sdev_target->scsi_level = SCSI_2;
> }
How about this:
sdev->sdev_target->scsi_level =
sdev->scsi_level = SCSI_2;
This makes it clear that the two values are intended always to be equal.
> The 0x1A is still there. I looked at the code and it seems observing
> use_10_for_ms everywhere. But also both sd and scsi_lib can reset it
> to zero if things go wrong, which is what may be happening. I think
> a couple of printks may clear up the picture.
Or usbmon. :-)
Speaking of which, and completely OT, I have a request for a usbmon API
change. When reporting an Isochronous URB, would it be possible to
present urb->number_of_packets? It would be useful for debugging.
Alan Stern
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