Re: raidframe: Initiating parity re-write time

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Thu, May 26, 2011 at 12:08:44PM +0200, uhel%gmx.net@localhost wrote:
> > > There is also another option in the BIOS that might be useful: 'Change
> > > the AHCI DID for Linux' but I have no clue what that means.
> > > 
> > > Aside of that, is it expected that the drive enumeration changes after
> > > switching to AHCI mode?
> > 
> > Yes, as all drives are master now
> 
> Ah okay, I thought with SATA thats always the case (independently of
> the driver) .

Yes, SATA is P2P connection and all drives are master (physically).
A SATA controller with a pciide programming interface will emulate
the IDE master/slave protocol, because this is what the pciide
programming interface offers.
When switched to AHCI mode, the controller offers a different (smarter)
programming interface in which each SATA port is an independant channel.

Some controllers offers only the pciide interface (most earlier SATA
controllers fall in this case). Some recent controllers can offer
the pciide or AHCI interface (but not both at the same time), they can be
switched from one mode to another from a register (usually the BIOS has a
switch for this).

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--