Return-path: Received: from mga09.intel.com ([134.134.136.24]:3765 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759907AbZCXOru convert rfc822-to-8bit (ORCPT ); Tue, 24 Mar 2009 10:47:50 -0400 From: "Guy, Wey-Yi W" To: Johannes Berg , Dan Williams CC: linux-wireless , Kalle Valo , Matthew Garrett , Marcel Holtmann Date: Tue, 24 Mar 2009 07:47:46 -0700 Subject: RE: wireless powersaving (in NM?) Message-ID: (sfid-20090324_154810_059379_6445E561) References: <1237891149.4320.73.camel@johannes.local> (sfid-20090324_133306_274219_3B7517AB) <1237902786.4320.92.camel@johannes.local> In-Reply-To: <1237902786.4320.92.camel@johannes.local> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi Johannes, Especially for Netbook and Handle devices with newer processor. Putting system into lower C-state and having longer battery life is very important. I think letting driver making the default choice based on the power source is the right way to go, but always can be overwritten by upper layer (mac80211 or NM?). I do not think we need to expose all the power levels to user space; those should be internal decision (mac80211 or driver). User space can make the choice of turn power saving mode on/off and leave the detail decision to the lower layer which has better knowledge of how to balance the power and performance. Wey-Yi Guy Intel Corporation 2111 N.E. 25th Avenue M/S JF3-308 Hillsboro OR 97124-5961 USA Work Phone: 503-264-6023 (OR) Cell Phone: 503-329-8410 Email: wey-yi.w.guy@intel.com -----Original Message----- From: Johannes Berg [mailto:johannes@sipsolutions.net] Sent: Tuesday, March 24, 2009 6:53 AM To: Dan Williams Cc: Guy, Wey-Yi W; linux-wireless; Kalle Valo; Matthew Garrett; Marcel Holtmann Subject: Re: wireless powersaving (in NM?) > Therefore, I think the "power saving level" needs to be determined by > pm_qos. Cf. http://www.lesswatts.org/projects/power-qos/ too, which is the old description of pm_qos, see Documentation/power/pm_qos_interface.txt too of course. johannes