Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753452AbZCLISz (ORCPT ); Thu, 12 Mar 2009 04:18:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752762AbZCLISj (ORCPT ); Thu, 12 Mar 2009 04:18:39 -0400 Received: from mx1.auerswald.de ([212.185.163.234]:2782 "EHLO mail.auerswald.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752497AbZCLISi convert rfc822-to-8bit (ORCPT ); Thu, 12 Mar 2009 04:18:38 -0400 From: Wolfgang =?iso-8859-1?q?M=FCes?= Organization: Auerswald GmbH & Co. KG To: "David Brownell" Subject: Re: [PATCH 5/7] mmc_spi: allow higher timeouts for SPI mode Date: Thu, 12 Mar 2009 09:16:27 +0100 User-Agent: KMail/1.9.10 Cc: "Matt Fleming" , "Pierre Ossman" , "Andrew Morton" , "Mike Frysinger" , linux-kernel@vger.kernel.org References: <200903111317.42696.david-b@pacbell.net> In-Reply-To: <200903111317.42696.david-b@pacbell.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200903120916.27797.wolfgang.mues@auerswald.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1552 Lines: 42 David, Am Mittwoch, 11. M?rz 2009 schrieb David Brownell: > I think you're confused. A *delay() call will busy-wait. > But a *sleep() call like msleep() will schedule. Yes. You are right. I was confused. Sorry for that. > (These speed concerns apply primarily to patch #6, not > this one ...) But I think the consequences of patch #6 are over-estimated. I have not noted a slowdown in filesystem I/O. Most responses are coming in while the loop is in busy-waiting. And for most embedded systems, it _is_ important to don't allow long periods of busy-waiting. There are other problems which are more notable: I have found that SDHC cards (with FAT32, clustersize = 4 KByte) are much SLOWER than the older SD cards (with FAT16, clustersize = 16-32 KByte). I will do some investigation here. best regards ? i. A. Wolfgang M?es -- Auerswald GmbH & Co. KG Hardware Development Telefon: +49 (0)5306 9219 0 Telefax: +49 (0)5306 9219 94 E-Mail: Wolfgang.Mues@Auerswald.de Web: http://www.auerswald.de ? -------------------------------------------------------------- Auerswald GmbH & Co. KG, Vor den Grash?fen 1, 38162 Cremlingen Registriert beim AG Braunschweig HRA 13289 p.h.G Auerswald Gesch?ftsf?hrungsges. mbH Registriert beim AG Braunschweig HRB 7463 Gesch?ftsf?hrer: Dipl-Ing. Gerhard Auerswald -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/