From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Is there a reliable way to ID a SSD? Date: Thu, 06 Jan 2011 13:55:30 -0500 Message-ID: <4D261022.3030902@garzik.org> References: <4D2223BF.8090901@canonical.com> <4D2247A3.2060506@canonical.com> <4D25E96D.10400@computer.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-qy0-f181.google.com ([209.85.216.181]:40214 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753129Ab1AFSzf (ORCPT ); Thu, 6 Jan 2011 13:55:35 -0500 Received: by qyk12 with SMTP id 12so18877762qyk.19 for ; Thu, 06 Jan 2011 10:55:34 -0800 (PST) In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Greg Freemyer Cc: Jan Ceuleers , "Peter M. Petrakis" , IDE/ATA development list , Tejun Heo On 01/06/2011 01:40 PM, Greg Freemyer wrote: > (resend, sorry for the duplicate) > > Jeff, > > As the maintainer, can you provide direction as to how quirks should > be maintained for the rotating disk flag (as reflected in > /sys/block/sda/queue/rotational). > > There is Bart's patch, Peter's patch, and Martin says it can be > overridden from userspace (I'm not sure which tool, nor do I know if > there is already a userspace quirks table to add to.). > > Bart's atang PATCH: http://marc.info/?l=linux-ide&m=126677421807814&w=2 > > Peter's patch: http://www.spinics.net/lists/linux-ide/msg38944.html There are a long list of non-rotational devices that were produced before the ATA standard grew a standard method of reporting that device attribute. That implies any approach individually listing products will create a very, very long horkage list containing all ATA flash drives that anyone ever produced. Alternately, scanning for the "SSD" string does not seem very useful, because it will only match a tiny minority of first-run products that (a) call themselves "SSD" in marketing literature but (b) do not indicate proper rotational attributes in the IDENTIFY page. Because while non-rotational products have been around for a very long time, "SSDs" as they are a currently known are new. It seems like a project to retroactively identify ATA non-rotational products will be long and on-going, and would be better suited to a userspace package such as Tejun's storage-fixup: http://git.kernel.org/?p=linux/kernel/git/tj/storage-fixup.git Jeff