From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: [patch update] Re: [linux-pm] Run-time PM idea (was: Re: [RFC][PATCH 0/2] PM: Rearrange core suspend code) Date: Thu, 11 Jun 2009 23:05:48 +0200 Message-ID: <200906112305.49232.oliver@neukum.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtp-out002.kontent.com ([81.88.40.216]:54925 "EHLO smtp-out002.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751656AbZFKVFA convert rfc822-to-8bit (ORCPT ); Thu, 11 Jun 2009 17:05:00 -0400 In-Reply-To: Content-Disposition: inline Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Alan Stern Cc: "Rafael J. Wysocki" , Linux-pm mailing list , ACPI Devel Maling List , LKML Am Donnerstag, 11. Juni 2009 20:36:30 schrieb Alan Stern: > > Or abstractly any power saving state that does autoresume in hardwa= re. > > In these cases you know that you can enter a powersaving state that > > will add X latency. > > > > In terms of user space API we'll probably add a way for user space > > to specify how much latency may be added for power management's sak= e. > > If busses are stacked the "latency budget" has to be handled at cor= e > > level. If furthermore states that allow IO but with additional late= ncy > > are ignored, the budget will be calculated wrongly. > > Okay, fine. =A0What does this have to do with Rafael's work? =A0Why d= oes > setting the status to RPM_SUSPENDED even when a device is not in a > low-power state preclude handling buses that automatically change the= ir > power state? =46or these cases the tree constraint does not apply. I think there are devices who can be suspended while children are activ= e and devices which can not be. This is an attribute of the device and sh= ould be evaluated by the core. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758533AbZFKVFN (ORCPT ); Thu, 11 Jun 2009 17:05:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753768AbZFKVFB (ORCPT ); Thu, 11 Jun 2009 17:05:01 -0400 Received: from smtp-out002.kontent.com ([81.88.40.216]:54925 "EHLO smtp-out002.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751656AbZFKVFA convert rfc822-to-8bit (ORCPT ); Thu, 11 Jun 2009 17:05:00 -0400 From: Oliver Neukum To: Alan Stern Subject: Re: [patch update] Re: [linux-pm] Run-time PM idea (was: Re: [RFC][PATCH 0/2] PM: Rearrange core suspend code) Date: Thu, 11 Jun 2009 23:05:48 +0200 User-Agent: KMail/1.10.3 (Linux/2.6.30-rc7-0.1-default; KDE/4.1.3; x86_64; ; ) Cc: "Rafael J. Wysocki" , "Linux-pm mailing list" , ACPI Devel Maling List , LKML References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200906112305.49232.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Donnerstag, 11. Juni 2009 20:36:30 schrieb Alan Stern: > > Or abstractly any power saving state that does autoresume in hardware. > > In these cases you know that you can enter a powersaving state that > > will add X latency. > > > > In terms of user space API we'll probably add a way for user space > > to specify how much latency may be added for power management's sake. > > If busses are stacked the "latency budget" has to be handled at core > > level. If furthermore states that allow IO but with additional latency > > are ignored, the budget will be calculated wrongly. > > Okay, fine.  What does this have to do with Rafael's work?  Why does > setting the status to RPM_SUSPENDED even when a device is not in a > low-power state preclude handling buses that automatically change their > power state? For these cases the tree constraint does not apply. I think there are devices who can be suspended while children are active and devices which can not be. This is an attribute of the device and should be evaluated by the core. Regards Oliver