From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751668AbcI1HnH (ORCPT ); Wed, 28 Sep 2016 03:43:07 -0400 Received: from mx2.suse.de ([195.135.220.15]:35766 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751021AbcI1Hm7 (ORCPT ); Wed, 28 Sep 2016 03:42:59 -0400 Message-ID: <1475048574.4635.1.camel@suse.com> Subject: Re: [PATCH 2/2] mfd: intel-lpss: Avoid resuming runtime-suspended lpss unnecessarily From: Oliver Neukum To: Chen Yu Cc: linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Len Brown , Pavel Machek , Lee Jones , linux-kernel@vger.kernel.org, Andy Shevchenko , Mika Westerberg , "Rafael J . Wysocki" Date: Wed, 28 Sep 2016 09:42:54 +0200 In-Reply-To: <6e14fa9659f23da041bc5e65edcd53c3e4845c74.1475032126.git.yu.c.chen@intel.com> References: <6e14fa9659f23da041bc5e65edcd53c3e4845c74.1475032126.git.yu.c.chen@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2016-09-28 at 11:28 +0800, Chen Yu wrote: > So first try is to use pm_request_resume() instead, to make the > runtime > resume process asynchronously. Unfortunately the asynchronous runtime > resume relies on pm_wq, which is freezed at early stage. So we choose > another method, that is to avoid resuming runtime-suspended devices, > if they are already runtime suspended. This is safe because for LPSS > driver, the runtime suspend and system suspend are of the same > hook - i.e., intel_lpss_suspend(). And moreover, this device is > neither runtime wakeup source nor system wakeup source. I agree with the reasoning but I don't see the specificity to LPSS. Shouldn't this go into the core? Regards Oliver