Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755019Ab1BVSQ3 (ORCPT ); Tue, 22 Feb 2011 13:16:29 -0500 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:46378 "EHLO opensource2.wolfsonmicro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754987Ab1BVSQ2 (ORCPT ); Tue, 22 Feb 2011 13:16:28 -0500 Date: Tue, 22 Feb 2011 10:16:48 -0800 From: Mark Brown To: john stultz Cc: rtc-linux@googlegroups.com, LKML , Thomas Gleixner , Alessandro Zummo , Marcelo Roberto Jimenez Subject: Re: [rtc-linux] [PATCH 04/10] RTC: Cleanup rtc_class_ops->read_alarm() Message-ID: <20110222181647.GA25569@opensource.wolfsonmicro.com> References: <1298332538-31216-1-git-send-email-john.stultz@linaro.org> <1298332538-31216-5-git-send-email-john.stultz@linaro.org> <20110222023452.GB18299@sirena.org.uk> <1298343333.4222.36.camel@work-vm> <1298362178.4222.57.camel@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1298362178.4222.57.camel@work-vm> X-Cookie: Q: How do you keep a moron in suspense? 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 Content-Length: 1243 Lines: 24 On Tue, Feb 22, 2011 at 12:09:38AM -0800, john stultz wrote: > Just so I can better get a grip of the cases your considering, could you > maybe give me some more detailed examples of where you'd like to see the > alarm timer be set and then persist across multiple power cycles before > firing? And how is that persistent value managed by the application > setting it? The WM83xx RTCs can do this (the alarm can be used to initiate a boot) and I'd expect many embedded RTC controllers can do similar. The application would manage this by owning the RTC in the system, usually with a configuration saying something like "boot every day at 7am" or something. Having thought about this a bit I'm thinking that this sort of alarm handling is probably something I'd expect to see handled in userspace. I can see us providing a virtual RTC driver that can generate alarms when there's no actual RTC hardware but adding additional functionality on top of the hardware feels like an application issue. -- 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/