From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timothy Thelin Subject: Re: TASKFILE ioctl for libata? Date: Fri, 17 Feb 2006 10:27:12 -0800 Message-ID: <1140200833.7509.101.camel@localhost> References: <20060215143439.GA17850@harddisk-recovery.com> <43F37A5E.1090301@rtr.ca> <20060216005643.GA28396@harddisk-recovery.com> <43F3E17E.1090701@pobox.com> <43F4461C.1080501@gmail.com> <43F58B7E.4000401@pobox.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from wdscexfe01.sc.wdc.com ([129.253.170.53]:32903 "EHLO wdscexfe01.sc.wdc.com") by vger.kernel.org with ESMTP id S1750821AbWBQS3m (ORCPT ); Fri, 17 Feb 2006 13:29:42 -0500 In-Reply-To: <43F58B7E.4000401@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Tejun Heo , Erik Mouw , Mark Lord , linux-ide@vger.kernel.org On Fri, 2006-02-17 at 03:38 -0500, Jeff Garzik wrote: > Tejun Heo wrote: > > Just a side note. Taskfile has finer granuality regarding which > > registers are written and read back than current libata does and IDE > > taskfile implementation is somewhat broken/weird in a few delicate fun > > ways, so... be careful. Whoever tries it. > > Yes -- it opens the question about whether we care enough to fully > support flagged taskfiles, and if not, how to best emulate that support > under libata. > > I'm told that flagging individual ATA shadow registers for modification > (or not) is required for issuing certain specialized PATA > vendor-specific commands. SATA, OTOH, transmits all ATA shadow > registers in a FIS, so flagged taskfiles are useless. > > So, I'm now thinking the best route is to leave the code as it is ;-) > Rather than imperfectly implementing the flagged taskfile ioctl, punt > the remaining userland users to SG_IO. > > I don't see lack of full flagged taskfile support as a big stumbling > block to libata use. > > Jeff FYI, Western Digital doesn't need flagged taskfile access to use its vendor specific commands; SAT passthru works fine (although we'd appreciate more of the protocols implemented, or at least a way to discover at runtime which ones are implemented before trying to use them). - Tim Thelin