From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: when limited to a single DRQ block per disk transaction Date: Fri, 14 May 2004 15:50:16 -0400 Sender: linux-ide-owner@vger.kernel.org Message-ID: <40A522F8.2080904@pobox.com> 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> <1084563455.8752.49.camel@patibmrh9> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:21696 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262388AbUENTu2 (ORCPT ); Fri, 14 May 2004 15:50:28 -0400 In-Reply-To: <1084563455.8752.49.camel@patibmrh9> List-Id: linux-ide@vger.kernel.org To: Pat LaVarre Cc: linux-ide@vger.kernel.org Pat LaVarre wrote: > Please can you say which controllers exhibit this limitation? AHCI. PIO is being deprecated... future ATA will be DMA-only. > Do we mean to be discussing a limit of one PATA DRQ INTRQ per CDB? Correct. If DRQ block size is 16 sectors, then each CDB is limited to a maximum of 16 sectors. This limit does not apply to DMA. Only to PIO, PIO multi, and ATAPI PIO. Jeff