From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mikael Pettersson Subject: Re: [RFC][PATCH] ahci: Add support for Promise PDC42819 Date: Thu, 4 Sep 2008 16:27:52 +0200 Message-ID: <18623.61544.364082.226862@harpo.it.uu.se> References: <65a6ef750809020403i52228319u9e3197e4062941bc@mail.gmail.com> <48BD2136.1020101@garzik.org> <65a6ef750809020455q7b7ee6a8jc404b4970f660c50@mail.gmail.com> <18621.11426.870514.781750@harpo.it.uu.se> <65a6ef750809020521wfaca733r8253795860b95f4@mail.gmail.com> <48BFBA5E.5050300@garzik.org> <65a6ef750809040459h3ffe3183nf0b5a35d15ab86e4@mail.gmail.com> <48BFE5FA.9090006@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from aun.it.uu.se ([130.238.12.36]:37084 "EHLO aun.it.uu.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbYIDO2h (ORCPT ); Thu, 4 Sep 2008 10:28:37 -0400 In-Reply-To: <48BFE5FA.9090006@garzik.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Mark Nelson , Mikael Pettersson , linux-ide@vger.kernel.org, linux-scsi Jeff Garzik writes: > Mark Nelson wrote: > > On Thu, Sep 4, 2008 at 8:37 PM, Jeff Garzik wrote: > >> Mark Nelson wrote: > >>> On Tue, Sep 2, 2008 at 10:08 PM, Mikael Pettersson wrote: > >>>> Mark Nelson writes: > >>>> > On Tue, Sep 2, 2008 at 9:19 PM, Jeff Garzik wrote: > >>>> > > Mark Nelson wrote: > >>>> > >> > >>>> > >> Add an appropriate entry for the Promise PDC42819 controller. It > >>>> has an > >>>> > >> AHCI mode and seems to work correctly with board_ahci. > >>>> > >> > >>>> > >> This chip is found on Promise's FastTrak TX2650 (2 port) and TX4650 > >>>> (4 > >>>> > >> port) > >>>> > >> software-based RAID cards (for which there is a binary driver, > >>>> t3sas) and > >>>> > >> can be found on some motherboards, for example the MSI K9A2 > >>>> Platinum, > >>>> > >> which calls the chip a Promise T3 controller. > >>>> > >> > >>>> > >> Signed-off-by: Mark Nelson > >>>> > >> --- > >>>> > >> Apparently this chip also supports SAS disks, will these work with > >>>> the > >>>> > >> ahci driver (I've only tested with normal desktop SATA disks)? > >>>> > > > >>>> > > ahci is definitely SATA-only, so I wonder how they modified AHCI to > >>>> support > >>>> > > SAS transport... > >>>> > > >>>> > That is a good question. From my understanding the controller is a SAS > >>>> > controller that can drive SATA disks (as I guess all SAS controllers > >>>> can > >>>> > do...). Could it be that the controller can be setup to act as an AHCI > >>>> > SATA controller or if the right registers are poked a SAS controller? > >>>> > >>>> Based on how the sata_promise-supported chips work I'd guess that they > >>>> have dual programming interfaces with AHCI for JBOD SATA and a native > >>>> one (perhaps just additional control registers) for SAS and raid. > >>>> > >>> That's interesting; and makes sense. I'm guessing that we won't end up > >>> with an open source driver that can do SAS on these chips then... But > >>> for now at least we can use them as SATA controllers and if Promise > >>> wants to come to the table with specs or datasheets they can in the > >>> future. I'm just happy to be able to use my eSATA ports (and perhaps > >>> the possibility of getting my hard disk off the SB600, although I should > >>> benchmark both controllers before jumping to any conclusions). > >> FWIW, I'll poke my Promise contacts, but they have gone mostly silent in the > >> past year, so don't get your hopes up... > > > > Thanks Jeff! > > > > No need for hope - we have ahci now :) > > Well, I still think this PCI ID addition leaves open the possibility > that plugging in a SAS disk could hang the system or similar misbehavior. Agreed, there's no telling what Promise-specific magic is needed to properly drive the T3. /Mikael