From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261949AbVFGSAm (ORCPT ); Tue, 7 Jun 2005 14:00:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261950AbVFGSAm (ORCPT ); Tue, 7 Jun 2005 14:00:42 -0400 Received: from mail.dvmed.net ([216.237.124.58]:24270 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S261949AbVFGSAi (ORCPT ); Tue, 7 Jun 2005 14:00:38 -0400 Message-ID: <42A5E0BF.8000103@pobox.com> Date: Tue, 07 Jun 2005 14:00:31 -0400 From: Jeff Garzik User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Kumar Gala CC: Linux Kernel list Subject: Re: stupid SATA questions References: <10d4b7cd189d7b661a84e765ab8cce93@freescale.com> In-Reply-To: <10d4b7cd189d7b661a84e765ab8cce93@freescale.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: 0.0 (/) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Kumar Gala wrote: > These questions were posed to me and I was hoping someone would have > better knowledge about the works and usage of SATA then I do. All of > these questions are around understanding how important the performance > of PIO mode is. > > How often would one run in PIO mode? Why would one run in PIO mode? Never. No idea. :) Unless you have a broken device, or a command that cannot work with DMA (such as IDENTIFY DEVICE), PIO mode is quite pointless. It is emulated under SATA, turned into FIS's on the SATA bus. Jeff