Return-path: Received: from mga02.intel.com ([134.134.136.20]:18752 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752196AbbISCpP (ORCPT ); Fri, 18 Sep 2015 22:45:15 -0400 Message-ID: <55FCCC37.9000503@linux.intel.com> (sfid-20150919_044541_949693_B44D7C14) Date: Sat, 19 Sep 2015 10:45:11 +0800 From: "Fu, Zhonghui" MIME-Version: 1.0 To: Johannes Berg , Arend van Spriel , Emmanuel Grumbach CC: David Miller , "linux-wireless@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Rafael J. Wysocki" Subject: Re: [PATCH] net/wireless: enable wiphy device to suspend/resume asynchronously References: <55B9B3BA.6080406@linux.intel.com> <55D13D66.1050500@linux.intel.com> <1439796553.2451.1.camel@sipsolutions.net> <55D19F57.4070605@broadcom.com> <55DA9374.2060909@linux.intel.com> <1440401918.3735.0.camel@sipsolutions.net> In-Reply-To: <1440401918.3735.0.camel@sipsolutions.net> Content-Type: text/plain; charset=utf-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2015/8/24 15:38, Johannes Berg wrote: > On Mon, 2015-08-24 at 11:45 +0800, Fu, Zhonghui wrote: >> On 2015/8/17 16:46, Arend van Spriel wrote: >>> + Rafael >>> >>> On 08/17/2015 09:29 AM, Johannes Berg wrote: >>>> On Mon, 2015-08-17 at 09:48 +0800, Fu, Zhonghui wrote: >>>>> The suspend/resume timing of wiphy device and related devices >>>>> will be >>>>> ensured by their parent/child relationship. So, enabling wiphy >>>>> device >>>>> to suspend/resume asynchronously does not change any >>>>> dependency. It >>>>> can only take advantage of multicore and improve system >>>>> suspend/resume speed. >>>>> >>>> You're going to have to explain that to me, because I don't see >>>> that. >>>> All I see is that when looking at a device, if async is possible, >>>> it >>>> gets added to an async work, and if async is not possible then it >>>> gets >>>> done immediately. Even putting aside the question of whether or >>>> not >>>> async is ordered or not (I don't know), if the wiphy is async and >>>> the >>>> PCI (or other bus) device isn't, then it seems they could get >>>> handled >>>> out of order, no? Or is there some magic code somewhere that I'm >>>> missing that explicitly waits for the async of the parent/child >>>> relationship? >>> This patch got me worried as well. Can't find the magic either. >>> Maybe Rafael can give some hints here. >> "dpm_wait_for_children" function will be invoked in >> "__device_suspend", "__device_suspend_late", and >> "__device_suspend_noirq" functions to synchronize the child >> relationship. "dpm_wait" function will be invoked in >> "device_resume_noirq", "device_resume_early", and "device_resume" >> functions to synchronize the parent relationship. If two devices have >> parent/child relationship, but different suspend/resume mode(sync or >> async), this will have no impact to PM timing order between them. >> Because all devices will use "__device_suspend", >> "__device_suspend_late" ... functions to complete their PM >> transition. >> > Ok, good point. For the unaware here, can you please resend with a > commit message amended with some of this information? I take some leaves these days, so very sorry for late reply. I have resent this patch with your advices - "[PATCH v2] net/wireless: enable wiphy device to suspend/resume asynchronously". Thanks, Zhonghui > > thanks, > johannes