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Message-ID: <4B4DAA68.60608@pobox.com>
Date: Wed, 13 Jan 2010 06:11:36 -0500
From: Jeff Garzik <jgarzik@pobox.com>
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To: Robert Hancock <hancockrwd@gmail.com>
CC: Seth Heasley <seth.heasley@intel.com>, linux-ide@vger.kernel.org,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.6.32.3] ahci: AHCI and RAID mode SATA patch for Intel
 Cougar Point DeviceIDs
References: <201001121700.18234.seth.heasley@intel.com> <4B4D4EAA.2010109@gmail.com>
In-Reply-To: <4B4D4EAA.2010109@gmail.com>
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On 01/12/2010 11:40 PM, Robert Hancock wrote:
> On 01/12/2010 07:00 PM, Seth Heasley wrote:
>> This patch adds the Intel Cougar Point (PCH) SATA AHCI and RAID
>> Controller DeviceIDs.
>>
>> Signed-off-by: Seth Heasley<seth.heasley@intel.com>
>>
>> --- linux-2.6.32.3/drivers/ata/ahci.c.orig 2010-01-06
>> 15:07:45.000000000 -0800
>> +++ linux-2.6.32.3/drivers/ata/ahci.c 2010-01-07 13:55:23.000000000 -0800
>> @@ -560,6 +560,12 @@
>> { PCI_VDEVICE(INTEL, 0x3b2b), board_ahci }, /* PCH RAID */
>> { PCI_VDEVICE(INTEL, 0x3b2c), board_ahci }, /* PCH RAID */
>> { PCI_VDEVICE(INTEL, 0x3b2f), board_ahci }, /* PCH AHCI */
>> + { PCI_VDEVICE(INTEL, 0x1c02), board_ahci }, /* CPT AHCI */
>> + { PCI_VDEVICE(INTEL, 0x1c03), board_ahci }, /* CPT AHCI */
>> + { PCI_VDEVICE(INTEL, 0x1c04), board_ahci }, /* CPT RAID */
>> + { PCI_VDEVICE(INTEL, 0x1c05), board_ahci }, /* CPT RAID */
>> + { PCI_VDEVICE(INTEL, 0x1c06), board_ahci }, /* CPT RAID */
>> + { PCI_VDEVICE(INTEL, 0x1c07), board_ahci }, /* CPT RAID */
>>
>> /* JMicron 360/1/3/5/6, match class to avoid IDE function */
>> { PCI_VENDOR_ID_JMICRON, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
>
> The RAID mode entries would be needed if the device indicates RAID class
> in that mode, but in plain AHCI mode it should indicate SATA AHCI class
> which will get picked up by this catch-all so those entries shouldn't be
> needed:
>
> /* Generic, PCI class code for AHCI */
> { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
> PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff, board_ahci },
>
> Likely a lot of the existing specific PCI IDs could be removed from the
> driver because of this (many likely predate the addition of the
> class-based catch-all). The only reason to need a specific entry if the
> device uses AHCI class is if it needs special handling or workarounds,
> which isn't the case here.

Well, two lines of thinking here:

* some of lines of Intel chips do not separate AHCI into a separate PCI 
ID rather legacy IDE interface.  When an AHCI interface exists and 
AHCI/IDE share the same PCI ID, we default to using AHCI.  Thus, some of 
those PCI ID matches in ahci.c's PCI table may not get caught by the 
generic PCI class match at the end of the table.

* the cost carrying redundant PCI IDs seems low, harmless, and 
potentially helpful.

Comments welcome, though...

	Jeff


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