From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754855AbaGPXJb (ORCPT ); Wed, 16 Jul 2014 19:09:31 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:50467 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754155AbaGPXJa (ORCPT ); Wed, 16 Jul 2014 19:09:30 -0400 From: "Rafael J. Wysocki" To: Alan Stern Cc: Greg Kroah-Hartman , Allen Yu , Pavel Machek , Len Brown , Dan Williams , Linux-pm mailing list , Kernel development list Subject: Re: [RFC] Add "rpm_not_supported" flag Date: Thu, 17 Jul 2014 01:27:45 +0200 Message-ID: <1961774.JeWiFOnpio@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20140716230345.GA3220@kroah.com> References: <1908592.0t6juNfLFj@vostro.rjw.lan> <20140716230345.GA3220@kroah.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, July 16, 2014 04:03:45 PM Greg Kroah-Hartman wrote: > On Thu, Jul 17, 2014 at 12:40:23AM +0200, Rafael J. Wysocki wrote: > > On Wednesday, July 02, 2014 10:27:06 AM Alan Stern wrote: > > > Here's a brief summary of the story behind this patch... > > > > > > At one point, I suggested to Dan that instead of doing something > > > special for these devices, we could simply have the runtime_suspend() > > > routine always return -EBUSY. He didn't like that idea because then > > > the user would see the device was never powering down but would have no > > > idea why. The rpm_not_supported flag provides this information to the > > > user by causing the power/runtime_status attribute to say "not > > > supported". (Although to be entirely fair, we could just put a message > > > in the kernel log during probe if the hardware doesn't support runtime > > > suspend.) > > > > > > Instead, Dan introduced a messy PM QoS mechanism in commit > > > e3d105055525. I didn't like that approach, but Greg merged it before I > > > objected. > > > > That really looks a bit like a hack to me to be honest. > > > > Greg, what's your plan toward this? > > If I need to revert something that you all find was wrong, I'll be glad > to do so, sorry for merging something too early. Alan, what do you think? I think we're still unsure if the approach taken by that commit is correct, but then I suppose we don't need to revert it at this point and we can fix it later. Is that correct, or would fixing it be difficult for some reason? Rafael