From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750738AbWG2WpZ (ORCPT ); Sat, 29 Jul 2006 18:45:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750740AbWG2WpZ (ORCPT ); Sat, 29 Jul 2006 18:45:25 -0400 Received: from home.keithp.com ([63.227.221.253]:8715 "EHLO keithp.com") by vger.kernel.org with ESMTP id S1750738AbWG2WpY (ORCPT ); Sat, 29 Jul 2006 18:45:24 -0400 Subject: Re: [PATCH] RTC: Add mmap method to rtc character driver From: Keith Packard To: Neil Horman Cc: keithp@keithp.com, Bill Huey , Jim Gettys , "H. Peter Anvin" , Dave Airlie , Segher Boessenkool , linux-kernel@vger.kernel.org, a.zummo@towertech.it, jg@freedesktop.org In-Reply-To: <20060729214334.GA8624@localhost.localdomain> References: <44C67E1A.7050105@zytor.com> <20060725204736.GK4608@hmsreliant.homelinux.net> <1153861094.1230.20.camel@localhost.localdomain> <44C6875F.4090300@zytor.com> <1153862087.1230.38.camel@localhost.localdomain> <44C68AA8.6080702@zytor.com> <1153863542.1230.41.camel@localhost.localdomain> <20060729042820.GA16133@gnuppy.monkey.org> <20060729125427.GA6669@localhost.localdomain> <20060729204107.GA20890@gnuppy.monkey.org> <20060729214334.GA8624@localhost.localdomain> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-J+9FAUi0dZspKFfzClxw" Date: Sat, 29 Jul 2006 15:45:19 -0700 Message-Id: <1154213119.28839.76.camel@neko.keithp.com> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-J+9FAUi0dZspKFfzClxw Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Sat, 2006-07-29 at 17:43 -0400, Neil Horman wrote: > Sure, an mmaped jiffy counter would certainly be usefull. I think the on= ly > thing left to be determined in this thread is if adding mmap to the rtc d= river > has any merit regardless of any potential users (iow, would current users= of > /dev/rtc find it helpful to have the rtc driver provide an mmap interface= .) A jiffy counter is sufficient for the X server; all I need is some indication that time has passed with a resolution of 10 to 20 ms. I check this after each X request is processed as that is the scheduling granularity. An X request can range in time from .1us to 100 seconds, so I really want to just check after each request rather than attempt some heuristic. --=20 keith.packard@intel.com --=-J+9FAUi0dZspKFfzClxw Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (GNU/Linux) iD8DBQBEy+T/Qp8BWwlsTdMRAh4WAKCdXKxUvYwHHKVCiIebXGMJUJJ09wCfQsr5 3RK2EfUFYrx/kw1edUQihO0= =zOr2 -----END PGP SIGNATURE----- --=-J+9FAUi0dZspKFfzClxw--