From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mga03.intel.com ([143.182.124.21]:12323 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755264Ab2AIBz4 (ORCPT ); Sun, 8 Jan 2012 20:55:56 -0500 Message-ID: <4F0A492A.5080504@intel.com> (sfid-20120109_025627_087966_ED2F3C31) Date: Mon, 09 Jan 2012 09:55:54 +0800 From: "Yan, Zheng" MIME-Version: 1.0 To: "Guy, Wey-Yi" CC: Johannes Berg , ilw@linux.intel.com, "netdev@vger.kernel.org" , linux-wireless Subject: Re: [PATCH RFC] iwlwifi: add basic runtime PM support References: <4F065F59.2070107@intel.com> <1325843269.3330.4.camel@jlt3.sipsolutions.net> <4F0A3C62.6010403@intel.com> <1326069251.13074.360.camel@wwguy-huron> In-Reply-To: <1326069251.13074.360.camel@wwguy-huron> Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 01/09/2012 08:34 AM, Guy, Wey-Yi wrote: > On Mon, 2012-01-09 at 09:01 +0800, Yan, Zheng wrote: >> On 01/06/2012 05:47 PM, Johannes Berg wrote: >>> [add linux-wireless] >>> >>> On Fri, 2012-01-06 at 10:41 +0800, Yan, Zheng wrote: >>>> This simple patch adds open/close based runtime PM support to the iwlwifi driver. >>>> Namely, make the driver suspend the device after shutting down the interface and >>>> resume the device when activating the interface. In my test, suspending the device >>>> can save about 0.4 watt power. The shortcoming is that the device no longer generate >>>> rfkill changes interrupt. >>> >>> NACK due to that last sentence. There's no way we can live with that in >>> the general case -- and your patch isn't even configurable afaict. And >>> I'm sure polling the rfkill flag would use just as much energy. >>> >> It's configurable, runtime PM is disabled by default. > > Somehow I miss it, how you configure it? > change the value of /sys/devices/.../power/control to auto to enable the runtime PM. (e.g echo auto > /sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/power/control) >> >>> There might be some value in this in a system that doesn't have a hard >>> rfkill line, but that means this needs to be configurable since the >>> device can't know whether there's a button or not [1]. >>> >> The patch targets system that only use software rfkill > > How you control that? I can't. Our team is working on runtime PM project, the purpose of the patch is more or less to demonstrate how much power can be saved. Regards Yan, Zheng