From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH] libata-core More robust parsing for multi_count(v5) Date: Sat, 21 Mar 2009 09:54:04 -0400 Message-ID: <49C4F17C.2030708@rtr.ca> References: <49C1047D.4000008@rtr.ca> <49C11A0C.3070502@rtr.ca> <49C11ED4.2030307@rtr.ca> <49C19087.5000307@gmail.com> <49C190F1.7010202@kernel.org> <49C28133.8050401@rtr.ca> <49C281A5.5080404@rtr.ca> <49C2D642.90706@kernel.org> <49C39690.6090802@rtr.ca> <49C396CF.7030202@rtr.ca> <20090320140714.2e7770d0@lxorguk.ukuu.org.uk> <49C3B7E9.2000505@rtr.ca> <49C4235D.5070303@kernel.org> <49C43ABA.4010601@pobox.com> <49C44E53.4020409@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:36411 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752737AbZCUNyN (ORCPT ); Sat, 21 Mar 2009 09:54:13 -0400 In-Reply-To: <49C44E53.4020409@kernel.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Jeff Garzik , Alan Cox , IDE/ATA development list Tejun Heo wrote: > Jeff Garzik wrote: >> Yeah, that has long been a design decision -- avoid all the mechanics of >> PIO-Multi, simply because we did not have much of a need for it (and >> still don't). >> >> Albert Lee worked on PIO-Multi a while ago, which was mainly to get >> ATA_{12,16} working, IIRC. >> >> But overall, I don't see much of a need to introduce it into the main >> stack? > > Well, there still are awful lot of PIO only devices out in the wild, > so improving PIO support seems like a good idea? .. Tons of CompactFlash cards are used PIO-only with Linux, and systems could benefit from the reduced interrupt overhead that multiple gives. Especially since those same systems tend to have rather modest embedded CPUs. We *already* do multiple-sector I/O in libata. But it currently works partially by accident, and probably gets shut off much of the time whenever the EH code is invoked and resets anything. Cheers