From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: Loud "pop" coming from hard drive on reboot Date: Wed, 18 Apr 2007 21:46:47 +0900 Message-ID: <46261337.3010406@gmail.com> References: <88SeR-5Sf-15@gated-at.bofh.it> <88Sov-662-3@gated-at.bofh.it> <88SHV-6uL-29@gated-at.bofh.it> <8agVk-3wc-81@gated-at.bofh.it> <8b3IR-4mE-25@gated-at.bofh.it> <8b3SA-4z3-5@gated-at.bofh.it> <8b42g-51N-15@gated-at.bofh.it> <8bbdm-7iS-27@gated-at.bofh.it> <46260981.1040109@gmail.com> <20070418132904.3322ba5f@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wr-out-0506.google.com ([64.233.184.233]:1549 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422958AbXDRMqy (ORCPT ); Wed, 18 Apr 2007 08:46:54 -0400 Received: by wr-out-0506.google.com with SMTP id 76so129537wra for ; Wed, 18 Apr 2007 05:46:53 -0700 (PDT) In-Reply-To: <20070418132904.3322ba5f@the-village.bc.nu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: 7eggert@gmx.de, Chuck Ebbert , emisca , Jan Engelhardt , Bartlomiej Zolnierkiewicz , linux-kernel , linux-ide@vger.kernel.org, Adrian Bunk , Andrew Morton Alan Cox wrote: >> Not that simple. Most disks don't spin up on SYNCHRONIZE_CACHE if its >> cache is clean. Sadly some disks actually spin up when it receives spin >> down command while spun down to immediately spin down again, so we would >> be fixing problem for some number of disks while breaking others. :-( > > Snoop the last command sent to the drive, that tells you if you can skip > the cache flush ? Thought about that and querying power state before doing shutdown sequence but things get somewhat ugly because shutdown sequence is driven from sd->shutdown(). We'll have to snoop both sync and shutdown commands and check whether the system is shutting down. Also, I felt very uneasy about faking successful completion to SYNCHRONIZE_CACHE. I dunno. It's already too late for 2.6.21. I was hoping we could get distros to update shutdown utilities in not-too-distant future but I have no experience with that. Is that just a wishful thinking? -- tejun