From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Subject: SATA device powerdown Date: Fri, 30 Jul 2010 13:59:56 +0100 Message-ID: <4C52CCCC.7010902@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:63092 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756667Ab0G3NAA (ORCPT ); Fri, 30 Jul 2010 09:00:00 -0400 Received: by wyb39 with SMTP id 39so1108384wyb.19 for ; Fri, 30 Jul 2010 05:59:58 -0700 (PDT) Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org Hi All, I have a question relating to the ATA drives and a SATA drive powerdown. Currently you can issue a HDD Spindown/Sleep command to a drive which will result in it going to sleep, but I have a hardware platform that requires the drive to be Powered-Off completely. (its in an extreme energy saving mode) Normal modes the HDD can sleep, and when any IO happens the disk wakes.. I can get the HDD to power-off when it enters deep-sleep (SMART register reading) but how can I get the disk to re-powered before next access is needed. Currently the /dev/sdx deregisters when the SATA bus is disconnected and re-registers when the device is avaliable. Is there a method to keep the open files alive when the HDD is powered off and execute a custom hardware relay switch to power the HDD back up and continue working with the files that were open previous to the sleep? Is this at all possible? Best Regards Richard