From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Date: Thu, 27 May 2010 18:16:44 +0100 Message-ID: <20100527171644.GA2468@srcf.ucam.org> References: <20100527003943.07c17f85@lxorguk.ukuu.org.uk> <20100527140655.GA28048@srcf.ucam.org> <20100527155201.GA31937@srcf.ucam.org> <20100527171615.15a1fd3d@lxorguk.ukuu.org.uk> <20100527161943.GA32764@srcf.ucam.org> <20100527170740.GA1980@srcf.ucam.org> <1274980391.27810.5552.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1274980391.27810.5552.camel@twins> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra Cc: Thomas Gleixner , Alan Cox , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Florian Mickler , Vitaly Wool , LKML , Paul@smtp1.linux-foundation.org, felipe.balbi@nokia.com, Linux OMAP Mailing List , Linux PM List-Id: linux-omap@vger.kernel.org On Thu, May 27, 2010 at 07:13:11PM +0200, Peter Zijlstra wrote: > On Thu, 2010-05-27 at 18:07 +0100, Matthew Garrett wrote: > > No. The useful property of opportunistic suspend is that nothing gets > > scheduled. That's fundamentally different to a deep idle state. > > I think Alan and Thomas but certainly I am saying is that you can get to > the same state without suspend. > > Either you suspend (forcefully don't schedule stuff), or you end up > blocking all tasks on QoS/resource limits and end up with an idle system > that goes into a deep idle state (aka suspend). > > So why isn't blocking every task on a QoS/resource good enough for you? Because you may then block them in such a way that they never handle an event that should wake them. -- Matthew Garrett | mjg59@srcf.ucam.org