From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: [git patches] libata hibernation fixes Date: Tue, 04 Nov 2008 18:20:29 -0600 Message-ID: <4910E6CD.9090605@mail.usask.ca> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from idcmail-mo1so.shaw.ca ([24.71.223.10]:64019 "EHLO idcmail-mo1so.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753867AbYKEAUe (ORCPT ); Tue, 4 Nov 2008 19:20:34 -0500 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Linus Torvalds Cc: Pavel Machek , Jeff Garzik , Andrew Morton , linux-ide@vger.kernel.org, LKML Linus Torvalds wrote: > > On Tue, 4 Nov 2008, Pavel Machek wrote: >> (Is park command normally supported on modern disks? IIRC hdaps people >> had issues with not all disks supporting it?) > > The modern version of parking is called "idle immediate". It may be that > only laptop drives support the "unload" part. But it's definitely not an > ancient and deprecated thing (although calling it "parking" is apparently > old-fashioned :) IDLE IMMEDIATE just transitions the device to the Idle state, which is normally parked/unloaded and spun down. Newer specs have an unload option, but really the only thing that does is tell the drive to do it immediately, even if read-ahead is in progress or there is dirty data in its write cache (something we definitely don't want to do if we're about to power down), it still spins down. It would be interesting to check Windows using QEMU or something to verify what exactly it's doing. I know Windows can run into this as well, on my Compaq X1000 laptop a shutdown from Windows also does a double spin-down on the hard drive. (However I replaced the original Hitachi drive with a Samsung, which might have different behavior.)