Re: No NCQ support on X61s Ultrabay? (Intel ICH8 SATA controller question)

[Matthew Wilcox <willy@linux.intel.com>]

On Fri, May 01, 2009 at 09:14:59AM -0400, Theodore Tso wrote:
> Gaah.... so basically a SATA device (the X25-M) is talking to a
> SATA-PATA bridge chip, which is then talking the IDE port in the ICH8
> chipset, which shows up as piix, which we're then pretending is SATA
> at the OS level via the ata_piix driver.  Did I get that right?
> (Excuse me while I go find a barf bag....)

Well ... libata doesn't pretend that everything is SATA; it uses
taskfiles which work for both PATA and SATA.  Other than that, I think
you've got it right.

> Oh.... and I suspect I know why they did it; I'm guessing they wanted
> to support PATA Ultrabay devices for backwards compatibility on the
> X60, and perhaps they were running out of connector pins on the
> docking station (the Ultrabay slot is on the X61's "media slice"), and
> they didn't have enough wires to run both PATA and SATA interfaces to
> the docking station, *and* they wanted to use the same docking station
> for the X60 and X61 Thinkpads.
> 
> Ah, well.  I hope it made sense to *someone* at Lenovo...  It would be
> interesting to see if they fixed this in the X200 or not.

Backwards compatibility is a pain.  It looks like from this lspci:
https://bugzilla.redhat.com/attachment.cgi?id=317327 that the X200 uses
ICH9M which doesn't appear to have an IDE port on the chip (document
316972-004).  So it must be fixed in the X200 ... unless they've put in
a SATA-PATA bridge in the base, and a PATA-SATA bridge in the ultrabay
...

Even then, it might work.  I don't know enough about the PATA protocol
to say.