From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: Reg. SATA II NCQ Date: Mon, 22 Jan 2007 14:59:44 +0900 Message-ID: <45B452D0.8030704@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ug-out-1314.google.com ([66.249.92.175]:46547 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751425AbXAVGAn (ORCPT ); Mon, 22 Jan 2007 01:00:43 -0500 Received: by ug-out-1314.google.com with SMTP id 44so966148uga for ; Sun, 21 Jan 2007 22:00:42 -0800 (PST) In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jaychander T Cc: linux-ide@vger.kernel.org Jaychander T wrote: > I understand from the SATA II NCQ specs that for NCQ commands(FPDMA) > we need not have to setup the DMA (PRD) for the commands issued but > has to do That's different thing. NCQ protocol doesn't require DMA SETUP FIS which is required for normal DMA commands but the controller still needs to be prepped with DMA table to know from/to where transfer data. > so only on reception of DMA setup FIS from the drive(throught ISR). > But in libata/ ata_qc_issue does qc prep and issue irrespective of the > protocol. Yeap, DMA table needs to be prepped whether NCQ is used or not. > Even i glanced thro' the sil24 driver and seems to be the same. The same for sil24. -- tejun