From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1758617Ab0EGVfM (ORCPT <rfc822;w@1wt.eu>);
	Fri, 7 May 2010 17:35:12 -0400
Received: from mail-pv0-f174.google.com ([74.125.83.174]:51594 "EHLO
	mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1758459Ab0EGVfK convert rfc822-to-8bit (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 7 May 2010 17:35:10 -0400
MIME-Version: 1.0
In-Reply-To: <1273267820.3542.120.camel@c-dwalke-linux.qualcomm.com>
References: <20100507180152.GH387@atomide.com>
	 <20100507184621.GA25978@srcf.ucam.org>
	 <1273259186.3542.93.camel@c-dwalke-linux.qualcomm.com>
	 <20100507192837.GM387@atomide.com>
	 <20100507193353.GA27175@srcf.ucam.org>
	 <20100507195548.GN387@atomide.com>
	 <20100507202859.GA27328@srcf.ucam.org>
	 <20100507205329.GP387@atomide.com>
	 <20100507210304.GA28701@srcf.ucam.org>
	 <1273267820.3542.120.camel@c-dwalke-linux.qualcomm.com>
Date: Fri, 7 May 2010 14:35:09 -0700
Message-ID: <p2vd6200be21005071435hf75ed42dnff2c2c02118e97@mail.gmail.com>
Subject: Re: [linux-pm] [PATCH 1/8] PM: Add suspend block api.
From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= <arve@android.com>
To: Daniel Walker <dwalker@fifo99.com>
Cc: Matthew Garrett <mjg@redhat.com>, Tony Lindgren <tony@atomide.com>,
       Brian Swetland <swetland@google.com>,
       Alan Stern <stern@rowland.harvard.edu>,
       mark gross <mgross@linux.intel.com>, markgross@thegnar.org,
       Len Brown <len.brown@intel.com>, linux-doc@vger.kernel.org,
       Kernel development list <linux-kernel@vger.kernel.org>,
       Jesse Barnes <jbarnes@virtuousgeek.org>,
       Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>,
       Linux-pm mailing list <linux-pm@lists.linux-foundation.org>,
       Wu Fengguang <fengguang.wu@intel.com>,
       Andrew Morton <akpm@linux-foundation.org>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, May 7, 2010 at 2:30 PM, Daniel Walker <dwalker@fifo99.com> wrote:
> On Fri, 2010-05-07 at 22:03 +0100, Matthew Garrett wrote:
>
>> Here's a different example. A process is waiting for a keypress, but
>> because it's badly written it's also drawing to the screen at 60 frames
>> per second and preventing the system from every going to idle. How do
>> you quiesce the system while still ensuring that the keypress will be
>> delivered to the application?
>
> To me it's somewhat of a negative for suspend blockers. Since to solve
> the problem you give above you would have to use a suspend blocker in an
> asynchronous way (locked in an interrupt, released in a thread too)
> assuming I understand your example. I've had my share of semaphore
> nightmares, and I'm not too excited to see a protection scheme (i.e. a
> lock) which allows asynchronous usage like suspend blockers.
>

Why do you think this? The example in the documentation describe how
we handle key events.


-- 
Arve Hjønnevåg