Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760437Ab0FKOqc (ORCPT ); Fri, 11 Jun 2010 10:46:32 -0400 Received: from netrider.rowland.org ([192.131.102.5]:51719 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1760384Ab0FKOqb (ORCPT ); Fri, 11 Jun 2010 10:46:31 -0400 Date: Fri, 11 Jun 2010 10:46:27 -0400 (EDT) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: James Bottomley cc: David Brownell , , Peter Zijlstra , Neil Brown , Brian Swetland , Felipe Balbi , LKML , Florian Mickler , Peter Zijlstra , Thomas Gleixner , Linux PM , Linux OMAP Mailing List , Linus Torvalds , Ingo Molnar , Alan Cox Subject: Re: [linux-pm] suspend blockers & Android integration In-Reply-To: <1276266502.2862.74.camel@mulgrave.site> 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: 1545 Lines: 35 On Fri, 11 Jun 2010, James Bottomley wrote: > On Thu, 2010-06-10 at 21:21 -0700, David Brownell wrote: > > Do we at least have a clean way that a driver can > > reject a system suspend? I've lost track of many > > issues, but maybe this could be phrased as a QOS > > constraint: the current config of driver X needs > > clock Y active to enter the target system suspend > > state, driver's suspend() method reports as much. Then the entry to > > that system state gets blocked > > if the clock isn't enabled. > > So in QoS modifications to android patches, the answer is "yes" ... > except that the current android patch set didn't actually have this type > of wakelock in it. > > Android wants an idleness suspend block (or pm qos constraint) that a > driver can set to prevent the system idleness power govenor from > dropping into a power state too low for the driver, so in USB terms this > would prevent the states that shut down the clock. For android, it > prevented shutdown of an internal i2c bus. > > The one thing that does look difficult is that these power constraints > are device (and sometimes SoC) specific. Expressing them in a generic > way for the cpu govenors to make sense of might be hard. Doesn't the clock framework already handle this sort of thing? 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/