From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964830AbWGYTIR (ORCPT ); Tue, 25 Jul 2006 15:08:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964821AbWGYTIR (ORCPT ); Tue, 25 Jul 2006 15:08:17 -0400 Received: from ra.tuxdriver.com ([70.61.120.52]:10248 "EHLO ra.tuxdriver.com") by vger.kernel.org with ESMTP id S964836AbWGYTIP (ORCPT ); Tue, 25 Jul 2006 15:08:15 -0400 Date: Tue, 25 Jul 2006 15:07:48 -0400 From: "John W. Linville" To: Arjan van de Ven Cc: Neil Horman , linux-kernel@vger.kernel.org, a.zummo@towertech.it, jg@freedesktop.org Subject: Re: [PATCH] RTC: Add mmap method to rtc character driver Message-ID: <20060725190743.GB31334@tuxdriver.com> References: <20060725174100.GA4608@hmsreliant.homelinux.net> <1153850139.8932.40.camel@laptopd505.fenrus.org> <20060725182208.GD4608@hmsreliant.homelinux.net> <1153852375.8932.41.camel@laptopd505.fenrus.org> <20060725184328.GF4608@hmsreliant.homelinux.net> <1153853596.8932.44.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1153853596.8932.44.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 25, 2006 at 08:53:16PM +0200, Arjan van de Ven wrote: > On Tue, 2006-07-25 at 14:43 -0400, Neil Horman wrote: > > alternative, which, as I mentioned before I would be happy to take a crack at, > > if you would elaborate on your idea a little more. > > well the idea that has been tossed about a few times is using a vsyscall > function that either calls into the kernel, or directly uses the hpet > page (which can be user mapped) to get time information that way... > or even would use rdtsc in a way the kernel knows is safe (eg corrected > for the local cpu's speed and offset etc etc). Aren't both of those examples x86(_64)-specific? Wouldn't a generic solution be preferrable? John -- John W. Linville linville@tuxdriver.com