Re: [usb-storage] [Merging ATA passthru] on integrating SMART/ATA-Security in usb-storage driver

[James Bottomley <James.Bottomley@SteelEye.com>]

On Sat, 2005-11-05 at 15:55 -0800, Matthew Dharm wrote:
> On Fri, Nov 04, 2005 at 02:49:55PM -0600, James Bottomley wrote: 
> > Can you just try it with a modern kernel and see if anything still
> > breaks?
> 
> I just realized this plan has a problem...
> 
> The reported SCSI level of a device is mostly garbage, but not always.
> I've seen 0, 1, 2, 3, and 0xff all reported.  HOWEVER, the reported value
> seems independent of what devices have vendor-specific commands (and thus
> need the CDB[1] not messed with).
> 
> It is an interesting experiment to remove the force-to-SCSI_2 part of the
> usb-storage code (on the general principal of "we shouldn't be messing with
> the data passed through the driver), but it doesn't solve the original
> question of needing a way to pass commands without CDB[1] getting altered.

Well, that might be a problem if it weren't for the fact that this
LUN_INHIBIT flag was removed in 2002.  If it's taken three years to find
a device that has a problem with it, I don't really think it's a
particularly widespread problem.  And since the device that now shows
the problem is setting the level to 0, it looks like we have a potential
solution that fits all known cases.

Anyway, the goal should be to handle devices in a standards compliant
manner first and then worry about quirk tables when that doesn't
work ... we have an incredibly broad quirk infrastructure in SCSI for
this.

James