From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933130Ab0E0WIk (ORCPT ); Thu, 27 May 2010 18:08:40 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:45385 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753843Ab0E0WIj (ORCPT ); Thu, 27 May 2010 18:08:39 -0400 Date: Thu, 27 May 2010 23:08:19 +0100 From: Matthew Garrett To: Alan Cox Cc: Peter Zijlstra , Thomas Gleixner , 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 Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Message-ID: <20100527220819.GA10602@srcf.ucam.org> References: <20100527161943.GA32764@srcf.ucam.org> <20100527170740.GA1980@srcf.ucam.org> <1274980391.27810.5552.camel@twins> <20100527171644.GA2468@srcf.ucam.org> <1274980856.27810.5582.camel@twins> <20100527172510.GC2468@srcf.ucam.org> <20100527223751.7af3b5ee@lxorguk.ukuu.org.uk> <20100527213635.GA9916@srcf.ucam.org> <20100527225637.57a336ad@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100527225637.57a336ad@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 27, 2010 at 10:56:37PM +0100, Alan Cox wrote: > On Thu, 27 May 2010 22:36:35 +0100 > Matthew Garrett wrote: > > No it doesn't. The kernel continues executing anything that was on the > > Would you like to come and watch my laptop resume ? With printk's if you > want. You appear at this point to be arguing that bumble bees can't > fly, while watching one. The kernel performs no explicit notification to userspace. With legacy graphics setups you'll get a VT switch, but X is entirely unaware that that's due to suspend and that's going away in any case. On a typical setup it's not even the kernel that does the VT switch to and from X - that's handled by a script that happens to be on the runqueue. So yeah, things kind of work as you suggest right now - but only by accident, not design. What you're describing requires a new interface to inform interested bits of userspace whenever you transition from your deep idle state into a less deep one. -- Matthew Garrett | mjg59@srcf.ucam.org