From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752490AbZDSV2Q (ORCPT ); Sun, 19 Apr 2009 17:28:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750944AbZDSV2A (ORCPT ); Sun, 19 Apr 2009 17:28:00 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:59154 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750902AbZDSV2A (ORCPT ); Sun, 19 Apr 2009 17:28:00 -0400 Message-ID: <49EB9758.3020506@garzik.org> Date: Sun, 19 Apr 2009 17:27:52 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: =?UTF-8?B?Um9nw6lyaW8gQnJpdG8=?= CC: Michael Tokarev , Mark Lord , linux-kernel@vger.kernel.org Subject: Re: Quick question about libata and hdparm References: <49EB1A33.7050808@rtr.ca> <49EB1C9C.3000105@msgid.tls.msk.ru> <49EB1FB3.5000609@garzik.org> <20090419201132.GB2891@ime.usp.br> In-Reply-To: <20090419201132.GB2891@ime.usp.br> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.2.5 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rogério Brito wrote: > Hi, Jeff. > > On Apr 19 2009, Jeff Garzik wrote: >> Michael Tokarev wrote: >>> Well, the kernel does a good job here in *almost* all cases. >>> The problematic case is when a device has some bad/unreadable >>> blocks/sectors. When such a place occurs on read, libata >>> (or whatever it is) performs several retries, each time >>> using "less aggressive" settings - like reducing UDMA and >>> PIO mode till the lowest possible PIO/33. And the device >>> stays in that mode until reboot, even if the problematic >>> sector has been relocated. So it'd be nice to be able to >>> reset the mode back in such cases. >> Do you have a log? > > I have a log here of libata reducing UDMA speed. I don't know if this is > any hardware problem or not (I think not), but I do see libata > complaining and reducing the speed of the drive. Well, it's supposed to reduce speed in several circumstances... just not Michael's. :) Jeff