From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pat LaVarre Subject: when limited to a single DRQ block per disk transaction Date: 14 May 2004 13:37:35 -0600 Sender: linux-ide-owner@vger.kernel.org Message-ID: <1084563455.8752.49.camel@patibmrh9> References: <1084393233.3999.2.camel@patibmrh9> <40A28BB6.7090204@pobox.com> <1084403654.3196.31.camel@patibmrh9> <40A3E595.8000003@pobox.com><108455 9 000.4017.52.camel@patibmrh9> <40A51604.8070208@pobox.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from email-out2.iomega.com ([147.178.1.83]:43729 "EHLO email.iomega.com") by vger.kernel.org with ESMTP id S262339AbUENTh7 (ORCPT ); Fri, 14 May 2004 15:37:59 -0400 In-Reply-To: <40A51604.8070208@pobox.com> List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: linux-ide@vger.kernel.org Jeff G: > > > Re: SATA ATAPI work in progress > > > ... > > > some AHCI SATA controllers can only transfer a _single_ DRQ block > > > per disk transaction. In anticipation of the demise > > > of PIO, no doubt :) > ... > for controllers that are limited to a single DRQ block per > disk transaction, Please can you say which controllers exhibit this limitation? > the OS driver _must_ limit each ATA taskfile to no > more than a DRQ block's worth of sector. If the ATAPI byte count limit > is 8K, then the OS driver must guarantee that a single ATA taskfile does > not transfer more than 8K. Please can you give an example of a disk transaction that doesn't work on some controllers? I ask because I think somehow even this late in our thread I do not yet understand what the limitation under discussion is. Do we mean to be discussing a limit of one PATA DRQ INTRQ per CDB? Pat LaVarre