Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756794AbZGHVJQ (ORCPT ); Wed, 8 Jul 2009 17:09:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754939AbZGHVJK (ORCPT ); Wed, 8 Jul 2009 17:09:10 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:35929 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754547AbZGHVJJ (ORCPT ); Wed, 8 Jul 2009 17:09:09 -0400 Date: Wed, 8 Jul 2009 17:09:08 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Rafael J. Wysocki" cc: Magnus Damm , Linux-pm mailing list , Greg KH , LKML , ACPI Devel Maling List , Ingo Molnar , Arjan van de Ven Subject: Re: [RFC][PATCH] PM: Introduce core framework for run-time PM of I/O devices (rev. 8) In-Reply-To: <200907082155.40903.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1283 Lines: 28 On Wed, 8 Jul 2009, Rafael J. Wysocki wrote: > > I thought you wanted to avoid this sort of complication. > > I did, but there might be some benefits. For example, the timer and the work > structure provided by dev.power can be used for scheduling such operations > if they are defined at the core level. > > Suppose your device has 3 low power states D1 - D3 (like PCI) and you want it > to go into D1 first, then, after a delay, to D2 and finally, again after a > delay, to D3. Of course, if there's a resume in the meantime, it should cancel > whichever transition is in progress. > > pm_runtime_suspend() can be used for the first transition, but the bus type or > driver will have to provide its own mechanics for going down to D2 and D3, > which must be synchronized with its ->runtime_resume(). That might be tricky > and the core already has what's necessary (well, almost). Maybe we can provide a way for drivers to set up their own timer callback or work routine for use while the status is RPM_SUSPENDED. Alan Stern -- 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/