Tejun,

Please see attached files.  The SATA chipset is identified as 0x8086 : 
0x27c0.  My _plain_ ICH7 is reported as:

00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) 
Serial ATA Storage Controllers cc=IDE (rev 01) (prog-if 8f [Master SecP 
SecO PriP PriO])
	Subsystem: Giga-byte Technology Unknown device b002
	Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 177
	I/O ports at d400 [size=8]
	I/O ports at d800 [size=4]
	I/O ports at dc00 [size=8]
	I/O ports at e000 [size=4]
	I/O ports at e400 [size=16]
	Capabilities: [70] Power Management version 2

The kernel source indicates both 0x27c0 (in ata_piix.c) and 0x27c1 (in 
ahci.c) are both ICH7.  The identifier naming also indicates that both 
do AHCI.  I don't think this is correct.

According the Intel's Specification Update for the ICH7 family:
(http://www.intel.com/design/chipsets/datashts/307013.htm - 30701417.pdf 
pg 11 is interesting for id purposes, but pg 22 contains the DIDs.)

	0x27c0 is Desktop Non-AHCI and Non-RAID Mode
	0x27c1 is Desktop AHCI Mode

Also Intel states:
	ICH7MDH - RAID only
	ICH7M - AHCI only
	ICH7R - RAID and AHCI
	ICH7DH - RAID and AHCI
	ICH7 - NO RAID, NO AHCI

( from http://www.intel.com/support/chipsets/imst/sb/CS-012304.htm )
(The main datasheet 30701302.pdf provides same info on pg 52)

The docs indicate that the Device IDs can change.  They represent the 
mode, not specifically the device.  But when we compare these sources we 
can conclude:

  - 0x27c0 is an ICH7 or, an ICH7DH or ICH7R (in non-AHCI/RAID mode)
  - 0x27c1 is not an ICH7 (Base)
  - 0x27c1 is an ICH7DH or ICH7R in AHCI mode

I would like to submit that the code comments in ahci.c be modified:

   { PCI_VDEVICE(INTEL, 0x27c1), board_ahci }, /* ICH7DH/ICH7R */

and in ata_piix.c:

/* 82801GB/GR/GH (ICH7/DH/R non-AHCI/non-RAID Mode, identical to ICH6)*/
   { 0x8086, 0x27c0, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },

Since 0x27c0 is *NOT* AHCI compatible, it seems to me that the 
driver_data member (ich6_sata_ahci) is incorrect.  What do you think?

Thanks,

Wayne


Tejun Heo wrote:
> Wayne Sherman wrote:
>> So, does the kernel source code incorrectly indicate some of these
>> chipsets are AHCI compatible?
> 
> Not really.  If the controller has PCI ID of 0x27c1, it's an ahci
> controller.  Care to post full dmesg and the result of 'lspci -nn'?
>