Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756667Ab3HZIu5 (ORCPT ); Mon, 26 Aug 2013 04:50:57 -0400 Received: from mail-la0-f44.google.com ([209.85.215.44]:42233 "EHLO mail-la0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751945Ab3HZIuy convert rfc822-to-8bit (ORCPT ); Mon, 26 Aug 2013 04:50:54 -0400 MIME-Version: 1.0 In-Reply-To: <35306580.ZCUI1aZasW@vostro.rjw.lan> References: <17024788.0xFN8jEV59@vostro.rjw.lan> <02318724-F4F7-4D53-9926-872E9417F672@freescale.com> <35306580.ZCUI1aZasW@vostro.rjw.lan> Date: Mon, 26 Aug 2013 16:50:53 +0800 X-Google-Sender-Auth: YHNUVOD3ynZt-2wnOJsbQitQ-lo Message-ID: Subject: Re: System suspend states and device driver suspend() callback From: Li Yang To: "Rafael J. Wysocki" Cc: Li Yang-R58472 , "linux-pm@vger.kernel.org" , lkml Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1655 Lines: 39 On Sat, Aug 17, 2013 at 7:53 AM, Rafael J. Wysocki wrote: > On Friday, August 16, 2013 05:13:42 PM Li Yang-R58472 wrote: >> >> 在 2013-8-16，下午7:22，"Rafael J. Wysocki" 写道： >> >> > On Friday, August 16, 2013 04:06:26 PM Li Yang wrote: >> >> Hi Guys, >> >> >> >> Is there a standard way for the device drivers to know if the system >> >> is going to “standby” mode or “mem” mode when the suspend() callbacks >> >> are called? >> > >> > No, there's none. >> > >> > What do you need that for? >> >> Some chips like ours are putting the on-chip devices into different low >> power states when entering different system low power states. When we enter >> system standby, on-chip devices are clock gated. While entering suspend to >> ram, on-chip devices are power gated. We want to driver to act differently >> too when entering different suspend states. > > Can you possibly use platform suspend operations to implement that (in analogy > with ACPI suspend operations)? I agree it's best to get the state that the device will be in during suspend from the platform code. Will it be better to have a standard interface to pass this information? Given the fact that a single device can be used by different platforms even different architecture nowadays. How about exposing some new callbacks from the platform_suspend_ops for the driver to use? Regards, Leo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/