From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [linux-pm] Runtime PM discussion notes Date: Sat, 30 Jul 2011 22:37:37 +0200 Message-ID: <20110730203737.GA8762@elf.ucw.cz> References: <201107131104.06995.rjw@sisk.pl> <20110729134015.GA1561@ucw.cz> <201107292152.27066.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:49743 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752226Ab1G3Uhk (ORCPT ); Sat, 30 Jul 2011 16:37:40 -0400 Content-Disposition: inline In-Reply-To: <201107292152.27066.rjw@sisk.pl> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Rafael J. Wysocki" Cc: Paul Walmsley , Mark Brown , linux-pm@lists.linux-foundation.org, linux-omap@vger.kernel.org Hi! > > Well, auto suspending when screensaver is active would still be > > useful. > > > > (And IIRC some machines kept screen on when in S-state unless driver > > powered it down... but that might be S1. > > > > > The reason why you can't enter ACPI S-states from CPUidle is because you > > > need to go out of the idle loop to execute some ACPI-specific stuff. Which > > > is not even specific to Intel chips, but to ACPI in general. > > > > The code was little tricky/unclean, but it "worked" for me at one > > point... I called it "sleepy linux". > > Yes, you can find a system where it might kind of work (just because > _PTS is empty or something like this). Is it going to work in general? > No way. IIRC I solved it by just calling _PTS when sleepy Linux was enabled. It had side effect of lighting up moon icon, but otherwise seemed to work ok. I do not think ACPI says what can and can not be done after _PTS... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html