From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757665AbcIVWE5 (ORCPT ); Thu, 22 Sep 2016 18:04:57 -0400 Received: from mga03.intel.com ([134.134.136.65]:37933 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757555AbcIVWE4 (ORCPT ); Thu, 22 Sep 2016 18:04:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,379,1470726000"; d="scan'208";a="12231196" Date: Thu, 22 Sep 2016 18:16:14 -0400 From: Keith Busch To: J Freyensee Cc: Jens Axboe , Andy Lutomirski , "linux-kernel@vger.kernel.org" , linux-nvme@lists.infradead.org, Andy Lutomirski , Christoph Hellwig Subject: Re: [PATCH v4 0/3] nvme power saving Message-ID: <20160922221613.GC14301@keith> References: <13b0fe95-01b8-89d7-df76-efc1aa14b27a@fb.com> <0a2ffd51-6e0f-7db3-8135-84317d8f77bc@fb.com> <1474580016.15303.31.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1474580016.15303.31.camel@linux.intel.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 22, 2016 at 02:33:36PM -0700, J Freyensee wrote: > ...and some SSDs don't even support this feature yet, so the number of > different NVMe devices available to test initially will most likely be > small (like the Fultondales I have, all I could check is to see if the > code broke anything if the device did not have this power-save > feature). > > I agree with Jens, makes a lot of sense to start with this feature > 'off'. > > To 'advertise' the feature, maybe make the feature a new selection in > Kconfig?  Example, initially make it "EXPERIMENTAL", and later when > more devices implement this feature it can be integrated more tightly > into the NVMe solution and default to on. Should we just leave the kernel out of this then? I bet we could script this feature in user space.