From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 1/2] libata: Remove dependence on host_set->dev for SAS Date: Thu, 01 Dec 2005 21:05:44 -0500 Message-ID: <438FABF8.3020802@pobox.com> References: <4341A91A.3020000@us.ibm.com> <435D5D83.1060201@us.ibm.com> <435D5DE5.7010306@us.ibm.com> <435E7105.4010105@pobox.com> <435E87E8.9010506@us.ibm.com> <435E8AC7.1080407@pobox.com> <435EB656.1040502@adaptec.com> <4360FAC1.8020409@us.ibm.com> <43850F0D.7040907@torque.net> <43851262.7020807@pobox.com> <58cb370e0511240012r64ad150eo90553b230992424e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:32989 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S964787AbVLBCFy (ORCPT ); Thu, 1 Dec 2005 21:05:54 -0500 In-Reply-To: <58cb370e0511240012r64ad150eo90553b230992424e@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Bartlomiej Zolnierkiewicz Cc: dougg@torque.net, brking@us.ibm.com, Luben Tuikov , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, t.schorpp@gmx.de Bartlomiej Zolnierkiewicz wrote: > On 11/24/05, Jeff Garzik wrote: > >>Douglas Gilbert wrote: >> >>>I don't think a SATL is that easy. One SCSI command can >>>translate into zero or more ATA commands. If it translates >>>to multiple commands, then there is the possibility of an >>>error prior to the last in the sequence of ATA commands >>>(how to report; rollback needed ?). The SATL needs to hold >>>state and needs a service thread if it is to support the >>>IMMED bit on some commands (e.g. START STOP UNIT). >> >>It needs a conceptual service thread, not necessarily an explicit one. >> >>With REQUEST SENSE, I've demonstrated how to report errors with each >>step in the sequence. With demo patches I've posted, I've demonstrated >>(using qc->private_data) how to hold state. >> >> >> >>>libata still has a ways to go to catch up to SAT rev 7 >>>but has made some good progress lately with the addition >>>of the ATA pass through commands (lk 2.6.15-rc1 and onward). >>>smartmontools (just prior to 5.34) now works with '-d ata' >>>on libata-connected SATA disks. The '-d ata' ** overrides >>>the guess of a SCSI disk based on the device node (e.g. >>>/dev/sda) and uses the HDIO_DRIVE_CMD and HDIO_DRIVE_TASK >>>ioctls. The absence of support for the HDIO_DRIVE_TASKFILE >>>ioctl means that "selective" self-test can't be done. >>>I'm not sure if moving smartmontools to the ATA PASS THROUGH >>>SCSI commands will win back the "selective" self-test >>>capability. Anyway, going to those ATA PASS THROUGH SCSI >> >>ATA passthru can do anything the legacy IDE ioctls can do (and more). > > > [ definitely ATA passthru is the way to go but... ] > > discrete taskfiles? what is this? > multi-PIO? what is this? multi-sector PIO, such as READ MULTIPLE SECTORS? ATA passthru can do that. > setting transfer speed? That's not a limitation of passthru, but a limitation of the driver. I don't yet see the value... Jeff