From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Koch Subject: [MX25][MMC]: SDHC very slow (300-600 KB/s) on i.MX25 board Date: Mon, 26 Nov 2012 11:42:46 +0100 Message-ID: <50B347A6.2020904@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f174.google.com ([209.85.217.174]:41973 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752359Ab2KZKmt (ORCPT ); Mon, 26 Nov 2012 05:42:49 -0500 Received: by mail-lb0-f174.google.com with SMTP id gi11so5536534lbb.19 for ; Mon, 26 Nov 2012 02:42:48 -0800 (PST) Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: linux-mmc@vger.kernel.org Hi, I have ported linux-3.7-rc4 to a board with i.MX257 CPU. As distribution I use Debian squeeze. Booting time (with Xorg and IceWM) is different with different SD-Cards. Boot time with 2GB Standard micro SD-Card: over 2:30 minutes Boot time with 4GB Class 10 micro SDHC: 1:40 minutes Boot time with 8GB UHS-1 micro SDHC: 1:15 minutes Boot time with NFS (Network without SD/SDHC): 40 seconds Starting applications is faster with NFS as with SD/SDHC. At SD/SDHC linux is system is waiting a lot of time. Then CPU can not run at 100% usage, so system is not so fast as possible. Tests with dd give ratings from a. e. 300 KB/s (this could be a Class 10 card). But there is a relationship with slower and faster SD/SDHC-cards: A UHS card works faster than a class 10 card an so on. And a Standard 2GB SD card is the slowest. But the Standard 2GB SC card works with a card reader connected to an Notebook faster than the UHS-1 Card in the imx257 Target system with imx integrated SDHC controller. How to solve this problem? Is it a driver issue? Thanks Stefan Koch