From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752627Ab1IZVDs (ORCPT ); Mon, 26 Sep 2011 17:03:48 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:44958 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294Ab1IZVDq (ORCPT ); Mon, 26 Sep 2011 17:03:46 -0400 To: Joshua Scoggins Cc: Alan Cox , Arun , linux-kernel@vger.kernel.org Subject: Re: Detection of Advanced Format drives From: "Martin K. Petersen" Organization: Oracle References: <20110926111522.2a053ceb@lxorguk.ukuu.org.uk> Date: Mon, 26 Sep 2011 17:01:42 -0400 In-Reply-To: (Joshua Scoggins's message of "Mon, 26 Sep 2011 12:48:46 -0700") Message-ID: User-Agent: Gnus/5.110017 (No Gnus v0.17) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Source-IP: rtcsinet21.oracle.com [66.248.204.29] X-CT-RefId: str=0001.0A020203.4E80E8AA.0073,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Joshua" == Joshua Scoggins writes: Joshua> Keep in mind that some AF drives will not report their actual Joshua> sector sizes. I have this issue with the WD AV-25 series. This Joshua> is to provide compatibility with older operating systems that Joshua> don't support AF drives. These are called generation 1 Joshua> devices. Newer drives will directly report their sector size as Joshua> 4096 through the drive identify data older ones will say 512. AF drives continue to report a logical block size of 512. There's an additional parameter in IDENTIFY DEVICE that describes the physical block size. Legacy operating systems do not check the physical block size parameter. Linux does, and will bubble this additional information up the stack. There have been a few attempts at switching ATA drives over to 4KB logical blocks as well. We are ready. However, both boot and legacy OS compatibility concerns make this a bit of an uphill battle. As you mention there's one vendor that pretty consistently gets their physical block size reporting wrong. We've pointed this out to them many times. Apparently it's been fixed with the latest green drive firmware... -- Martin K. Petersen Oracle Linux Engineering