RFC: ATA to CAM integration patch

[Dan Nelson]

In the last episode (Jun 29), Scott Long said:
> Ulrich Spörlein wrote:
> > On Sat, 27.06.2009 at 12:06:04 -0600, Scott Long wrote:
> >> Alexander Motin wrote:
> >>> This is not a problem. ATA disks does not have SCSI INQUIRY command. 
> >>> They use own IDENTIFY instead.  inquiry should work for ATAPI devices,
> >>> as they are SCSI deep inside.
> >> This is really the big missing piece in camcontrol; we need to add
> >> support for getting the IDENT info and getting/setting various
> >> attributes, as well as sending ATA commands over passthrough.
> > 
> > not sure if this is related, but I always wondered why tools like
> > smartctl never work with USB attached ATA disks.  Is it missing support
> > in our drivers and smartctl or is it simply impossible?
> 
> The possibility depends on several hardware and software factors.  If the
> USB disk enclosure was speaking ATA all the way up to the umass driver,
> then it could be possible to add some extra intelligence to the driver to
> make SMART work.  However, if the enclosure chip is speaking anything
> else, then probably not.  As an alternative, you might try to the ata-usb
> module instead and see if that works.

It also depends heavily on which USB bridge chip is in your external
enclosure.  See these links for a table of known good/bad enclosures:

http://smartmontools.wiki.sourceforge.net/USB 
http://smartmontools.wiki.sourceforge.net/overview_USB-Support
 
-- 
	Dan Nelson
	dnelson at allantgroup.com