Re: [PATCH 2.6.32.3] ahci: AHCI and RAID mode SATA patch for Intel Cougar Point DeviceIDs

[Krzysztof Halasa <khc@pm.waw.pl>]

Robert Hancock <hancockrwd@gmail.com> writes:

> Well, ata_piix does have a couple of entries that are listed in ahci
> as well, for ICH6 device IDs 0x2652 and 0x2653. For 0x2653 ata_piix
> checks the class code to make sure it's IDE, but for the 0x2652 entry,
> and in both cases in ahci, the class code isn't checked. Deleting the
> specific entries from ahci for those controllers would seemingly
> actually improve the situation, since then ahci wouldn't try and
> attach to those devices when they indicate IDE class. ata_piix should
> also should be checking for IDE class on 0x2652 as well.

Interestingly the ICH6* datasheet says:
2651 is plain ICH6 (not RAID/AHCI capable)
2652 is ICH6R
2553 is ICH6-M

The subclass code is:
for plain ICH6: 01 (IDE controller)
for ICH6R: 04 (RAID controller)
for ICH6-M: 01 (IDE) or 06 (SATA=AHCI)

I think later chips change their subclass depending on
IDE/AHCI/RAID BIOS setting, wasn't it the ICH6R case as well?

Not checking the subclass for ICH6-M in ahci driver may be a bug,
unless ahci can handle the chip in BIOS-set IDE mode. Not checking
ICH6R code (or checking only for RAID) seems right, though.
-- 
Krzysztof Halasa