From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Mon, 13 Feb 2012 09:26:34 -0800 Subject: Internal timers in deep sleep In-Reply-To: References: Message-ID: <20120213172633.GA1426@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Marcus, * Marcus Folkesson [120211 03:37]: > Is it possible to speed up the time it takes to go to/from deepsleep? > The pm_suspend() does a lot of things, eg. freeze processes, suspend > drivers and so on. Depending on the omap, you can already do suspend while idle or off while idle. This means the RAM is in self-refresh and the omap is either suspended or powered off in the idle loop. This is typically done with a combination of constantly running 32 KiHz clocksource and wake-up capable GPT1 clockevent timer. If you have similar timers on your hardware, this may be the way to go. In this case there's no need to freeze processes, so the latency is quite minimal. Regards, Tony From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757345Ab2BMR0i (ORCPT ); Mon, 13 Feb 2012 12:26:38 -0500 Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:40174 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755496Ab2BMR0h (ORCPT ); Mon, 13 Feb 2012 12:26:37 -0500 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 98.234.237.12 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1/2cmZZd+b3ACwHtoc5s1EV Date: Mon, 13 Feb 2012 09:26:34 -0800 From: Tony Lindgren To: Marcus Folkesson Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: Internal timers in deep sleep Message-ID: <20120213172633.GA1426@atomide.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marcus, * Marcus Folkesson [120211 03:37]: > Is it possible to speed up the time it takes to go to/from deepsleep? > The pm_suspend() does a lot of things, eg. freeze processes, suspend > drivers and so on. Depending on the omap, you can already do suspend while idle or off while idle. This means the RAM is in self-refresh and the omap is either suspended or powered off in the idle loop. This is typically done with a combination of constantly running 32 KiHz clocksource and wake-up capable GPT1 clockevent timer. If you have similar timers on your hardware, this may be the way to go. In this case there's no need to freeze processes, so the latency is quite minimal. Regards, Tony