Re: RFC: ACPI/scsi/libata integration and hotswap

Matthew Garrett
2005-12-10T02:47:51Z

On Fri, Dec 09, 2005 at 09:39:21PM -0500, Jeff Garzik wrote:
> Matthew Garrett wrote:
> >On Fri, Dec 09, 2005 at 07:40:08PM -0500, Jeff Garzik wrote:
> >
> >
> >>ICH6 and ICH7 support it just fine, through the normal SATA PHY
> >>registers. ICH5 only support it if you are clever :)
> >
> >
> >ICH6 supports it even in non-AHCI mode? You may want to update the
> >website, then :)
>
> Yes, its a bit outdated. I just found out that ICH6/7 supports access
> to SATA PHY registers even in non-AHCI mode.

Oh, cool. That makes life a /lot/ easier - most laptops I've seen using
SATA are ICH6, so excellent!

> >>Further, although one can detect hot-unplug on ICH5, hotplug is probably
> >>not detectable without polling or SMI.
> >
> >
> >ACPI allows us to detect hotplug on ICH5, which sounds like a good
> >argument for its inclusion.
>
> One special case (ICH5 hotplug, but not ICH5 hot unplug), when all other
> cases are handled in the normal way?
>
> That's not a good argument at all.

Well, we could always just add it to ata_piix and leave it out of the
acpi and scsi layers. I've no great atachment to ACPI - I just want this
stuff to work :) Basically, ACPI gives us the possibility of making
hotplug/unplug work on hosts that don't otherwise support it under a
limited set of conditions. I think that's worthwhile, especially if it
can be done in a way that doesn't introduce hugely ugly stuff to the
rest of the kernel.

--
Matthew Garrett | mjg59@srcf.ucam.org