From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263208AbVGOFXQ (ORCPT ); Fri, 15 Jul 2005 01:23:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263211AbVGOFXP (ORCPT ); Fri, 15 Jul 2005 01:23:15 -0400 Received: from b.mail.sonic.net ([64.142.19.5]:46299 "EHLO b.mail.sonic.net") by vger.kernel.org with ESMTP id S263208AbVGOFVx (ORCPT ); Fri, 15 Jul 2005 01:21:53 -0400 Date: Thu, 14 Jul 2005 22:21:39 -0700 From: David Hinds To: somshekar.c.kadam@in.abb.com Cc: linux-kernel@vger.kernel.org Subject: Re: Sandisk Compact Flash Message-ID: <20050715052139.GA7788@sonic.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 13, 2005 at 07:04:38PM +0530, somshekar.c.kadam@in.abb.com wrote: > > I ma newbie to compactflash driver , I am using mpc862 PPC processor > on my custom board having 64mb ram running linuxppc-2.4.18 kernel . > i am using Sandisk Extreme CF 1GB which is 133x high speed, but > found the performance with other kingston 1GB CF with slower speed , > is both same , CF is implemented on pcmcia port , i am not sure what > is the mode set for transfer , Feature set command is used in which > it sets the PIO mode or Multiword DMA transfer mode by specifying > its value in Sector count register , i am not able to understand in > linux kernel ide driver where this is set , is it by default set , > this mode is set or we need to set it , i think we should assign > this value , right now i am not able to trace this in my code. , All Compact Flash cards, in 16-bit PCMCIA card readers, operate in PIO mode 1 (polled IO, no DMA), which means you will get only about 1 MB/sec regardless of the card's claimed tranfer speed. Some cameras also only support this mode; others will run CF cars in "TrueIDE" mode, which is required to use the DMA transfer modes. There are high performance CF card readers that can use TrueIDE mode: both CardBus ones and Firewire ones. For example: http://www.dpreview.com/news/0310/03102103delkincardbustest.asp It sounds like your card reader is one of the slow 16-bit ones. -- Dave