From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata: increase LBA48 max sectors to 65535 Date: Mon, 20 Feb 2006 06:23:20 -0500 Message-ID: <43F9A6A8.4020606@pobox.com> References: <1139754779159-git-send-email-htejun@gmail.com> <43EF8E61.5040409@pobox.com> <43EFD73D.4070207@gmail.com> <43F011DF.6020203@pobox.com> <20060215072449.GA31691@htj.dyndns.org> <20060215130725.GP4203@suse.de> <43F342E6.9060909@gmail.com> <20060215151200.GW4203@suse.de> <43F38D49.4080601@pobox.com> <43F3B3CE.5060105@pobox.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]:60115 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932569AbWBTLXl (ORCPT ); Mon, 20 Feb 2006 06:23:41 -0500 In-Reply-To: <43F3B3CE.5060105@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Jens Axboe , Tejun Heo , albertcc@tw.ibm.com, linux-ide@vger.kernel.org Mark Lord wrote: > Jeff Garzik wrote: >> As an aside, I wonder if the PRD limit is unnecessarily low. I don't >> remember seeing anything that claimed we were limited to 256 s/g >> entries in the old IDE docs? > Well, originally I wrote ide-dma.c with a 256 PRD limit, > because that corresponds to the absolute worst case of > only one sector per PRD. The pre-LBA48 protocol cannot > read/write more than that with a single command. > > But nowadays.. Indeed. I am paranoid about controllers assuming that no more than 256 PRD entries will be submitted. But I have never seen any document that says PCI IDE BMDMA hardware can -only- do 256 PRD entries. Never tested it, either... Jeff