From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Jacob Subject: Re: qla2xxx and feral ISP updates in their respective BK trees Date: Fri, 20 Jun 2003 15:06:55 -0700 (PDT) Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030620150609.I305@wonky.in0.lcl> References: <1055971780.2075.484.camel@mulgrave> <20030620101224.B305@wonky.in0.lcl> <1056129548.2102.19.camel@mulgrave> <20030620102448.O305@wonky.in0.lcl> <1056133068.1804.22.camel@mulgrave> <20030620183417.GB9164@gtf.org> <20030620113759.B305@wonky.in0.lcl> <3EF383D1.7070900@pobox.com> Reply-To: mjacob@feral.com Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from beppo.feral.com ([192.67.166.79]:7693 "EHLO beppo.feral.com") by vger.kernel.org with ESMTP id S264942AbTFTVya (ORCPT ); Fri, 20 Jun 2003 17:54:30 -0400 In-Reply-To: <3EF383D1.7070900@pobox.com> List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: James Bottomley , SCSI Mailing List , Andrew Vasquez , Andrew Morton > Matthew Jacob wrote: > > a) Historically, MMIO has been buggy on ia32. This is no longer the > > case, but there definitely were a lot of platforms with this broken. > > Could you elaborate? > > What I've mostly found is (in order of frequency): coders unfamiliar > with x86 CPU write coalescing/posting rules, and PCI boards whose > hardware designs contain inherent races when driven in MMIO mode > (particularly on CPUs with deeply posted writes). The latter, I believe. > > > > b) MMIO is consumption of mapping resources, while PIO isn't. > > agreed > > Jeff > > > >