Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760182Ab0FQWXj (ORCPT ); Thu, 17 Jun 2010 18:23:39 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:57965 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759560Ab0FQWXi convert rfc822-to-8bit (ORCPT ); Thu, 17 Jun 2010 18:23:38 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=CODskh2OtqHHWSOqlKtImMYJNAwWd1yUEMLMrJInm5uuWuzALCd9a/XRpq1pk+JAyj pC6oiT8TQzu2/pQaZk829BavubDa1SjprRP2lbCdamA/VywllvAv7IPahJ4b73V2f94R zkSuA95AGvq+r7SUjMugJjuo2CGk9S6evkaxA= MIME-Version: 1.0 In-Reply-To: References: <0F1C0B07-60D6-405B-890B-F9C320820CA5@gmail.com> Date: Thu, 17 Jun 2010 17:23:35 -0500 Message-ID: Subject: Re: [linux-pm] RFC: /sys/power/policy_preference From: Victor Lowther To: Len Brown Cc: Linux Power Management List , Linux Kernel Mailing List , "linux-acpi@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 37 On Thu, Jun 17, 2010 at 2:02 PM, Len Brown wrote: > >> On Jun 16, 2010, at 4:05 PM, Len Brown wrote: >> >> > Create /sys/power/policy_preference, giving user-space >> > the ability to express its preference for kernel based >> > power vs. performance decisions in a single place. >> > >> > This gives kernel sub-systems and drivers a central place >> > to discover this system-wide policy preference. >> > It also allows user-space to not have to be updated >> > every time a sub-system or driver adds a new power/perf knob. >> >> I would prefer documenting all the current knobs and adding them to pm-utils >> so that pm-powersave knows about and can manage them. Once that is done, >> creating arbitrary powersave levels should be fairly simple. > > > The idea here is to not require user-space to need updating > whenever a future knob is invented. ?We can do a great job > at documenting the past, but a poor job of documenting the future:-) Well, I would suggest that the habit of not documenting what is happening with power management in the kernel needs to change, then. Having the documentation and example code for how to tweak the various power management settings from userspace is inherently more flexible than trying to expose a single knob from the kernel to userspace for power management, with little loss of flexibility. > cheers, > Len Brown, Intel Open Source Technolgy Center > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/