From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [RFC] AHCI Command Completion Coalescing(CCC) proposal Date: Fri, 09 Jun 2006 00:12:41 -0400 Message-ID: <4488F539.4010501@pobox.com> References: <1149751860.29552.79.camel@forrest26.sh.intel.com> <44883BAE.7070406@pobox.com> <1149820043.5721.7.camel@forrest26.sh.intel.com> <4488EB4A.4050501@pobox.com> <4488EE69.7050907@gmail.com> <4488EF64.9070602@gmail.com> <1149825065.5721.22.camel@forrest26.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:15078 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S965062AbWFIEMp (ORCPT ); Fri, 9 Jun 2006 00:12:45 -0400 In-Reply-To: <1149825065.5721.22.camel@forrest26.sh.intel.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: "zhao, forrest" Cc: Tejun Heo , linux-ide@vger.kernel.org zhao, forrest wrote: > On Fri, 2006-06-09 at 12:47 +0900, Tejun Heo wrote: >> If we're gonna do it. EH needs only a few changes probably during >> autopsy and report. Fixing up command issue path and implementing >> command exclusion (NCQ vs. non-NCQ, sil24 does it in hardware, ahci >> doesn't) will be a bit complex though. > > Would you please elaborate on command exclusion? Why NCQ commands need > to be excluded from non-NCQ commands? For one thing, getting the command ordering right (particularly with regards to barriers) isn't trivial... also, you need exclusion for major feature changes like set xfer mode. Jeff