Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756120AbZFHOah (ORCPT ); Mon, 8 Jun 2009 10:30:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752025AbZFHOa3 (ORCPT ); Mon, 8 Jun 2009 10:30:29 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:46208 "EHLO vavatch.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130AbZFHOa3 (ORCPT ); Mon, 8 Jun 2009 10:30:29 -0400 Date: Mon, 8 Jun 2009 15:30:23 +0100 From: Matthew Garrett To: Ingo Molnar Cc: Oliver Neukum , "Rafael J. Wysocki" , Alan Stern , pm list , ACPI Devel Maling List , LKML , Magnus Damm Subject: Re: Run-time PM idea (was: Re: [linux-pm] [RFC][PATCH 0/2] PM: Rearrange core suspend code) Message-ID: <20090608143023.GA16752@srcf.ucam.org> References: <20090608131159.GA15100@srcf.ucam.org> <20090608132235.GC13214@elte.hu> <200906081539.20459.oliver@neukum.org> <20090608142154.GD14234@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090608142154.GD14234@elte.hu> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@codon.org.uk X-SA-Exim-Scanned: No (on vavatch.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1195 Lines: 27 On Mon, Jun 08, 2009 at 04:21:54PM +0200, Ingo Molnar wrote: > The kernel _needs_ to have precise information about whether a piece > of hardware is in use or not. The kernel can only have that information if userspace tells it. What we're quibbling over is whether the kernel should be explicitly told about the requirement (ie, every time an app makes a key grab in X the kernel gets told about it) or whether it should be implicit (userspace knows that a key grab has been made and so requests that the keyboard not be suspended). We *can* put all of that complexity in the kernel. The question is whether it buys us anything. We'd have to modify huge chunks of userspace and in the process we'd end up limited to whatever policy happens to exist in the version of the kernel the user is running. I'd like the kernel to expose this functionality but leave the policy decisions to userland. -- Matthew Garrett | mjg59@srcf.ucam.org -- 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/