hot plugging eSATA

[Lennart Sorensen]

On Sat, Apr 03, 2010 at 12:14:33PM -0400, D. Hugh Redelmeier wrote:
> Thanks for this clue.
> 
> I tried hotp lugging eSATA on my machine (HP Pavilion a6245n desktop
> with Intel G33 and ICH9R chipset).  It didn't seem to work.
> 
> I went to the BIOS and found
> 	Advanced: SATA1 controller mode [IDE]
> 	SATA2 Controller [Enabled]
> I switched to
> 	Advanced: SATA1 controller mode [AHCI]
> and the SATA2 line disappeard?!?
> 
> I rebooted and hot plugging worked.  At least kind of.
> 
> Lessons:
> - all SATA controllers support hot plug

No they don't.

> - generally only in AHCI mode

AHCI does, but a lot of older controllers are NOT AHCI.

> - some (lots?) of BIOSes have setting that sets the mode

True.

> - the default setting may be IDE or ATA preventing hot plug

Also true.

> - the reason might be that some versions of Windows don't come whith
>   AHCI drivers.

Like XP.

And intel has been an ass in that they only provide AHCI drivers for
their older chipsets (like yours) if it is the R version (so ICH9R has
AHCI drivers, ICH9 does not).  No actual good reason, they just don't
want to.  They even told board makers to remove AHCI options from boards
using the ICH9 (which is why my board now runs a BIOS from a board with
the ICH9R that is otherwise identical in every other way).  I simply
have a P5K running a P5KR bios.  That way I can run AHCI which is pretty
much essential with more than 4GB ram (since in IDE/compatible mode it
is only 32bit DMA capable and uses bounce buffers which have trouble
keeping up, while AHCI is 64bit DMA capable and works great, and allows
hotplug drive changes).

-- 
Len Sorensen
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