From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262747AbTKIRux (ORCPT ); Sun, 9 Nov 2003 12:50:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262750AbTKIRux (ORCPT ); Sun, 9 Nov 2003 12:50:53 -0500 Received: from draal.physics.wisc.edu ([128.104.222.75]:41150 "EHLO moya.mcelrath.org") by vger.kernel.org with ESMTP id S262747AbTKIRuv (ORCPT ); Sun, 9 Nov 2003 12:50:51 -0500 Date: Sun, 9 Nov 2003 09:44:36 -0800 From: Bob McElrath To: Ivan Kokshaysky Cc: linux-kernel@vger.kernel.org Subject: Re: /dev/rtc on alpha Message-ID: <20031109174436.GA24812@mcelrath.org> Mail-Followup-To: Ivan Kokshaysky , linux-kernel@vger.kernel.org References: <20031108213356.GD16295@mcelrath.org> <20031109142435.A4596@jurassic.park.msu.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="SUOF0GtieIMvvwua" Content-Disposition: inline In-Reply-To: <20031109142435.A4596@jurassic.park.msu.ru> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --SUOF0GtieIMvvwua Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Ivan Kokshaysky [ink@jurassic.park.msu.ru] wrote: > On Sat, Nov 08, 2003 at 01:33:57PM -0800, Bob McElrath wrote: > > Why is the alpha kernel code grabbing the rtc interrupt? Is it possible > > it share its use with a user program? Would reprogramming the interrupt > > rate by a user program do violence to some internel kernel timing? >=20 > On most Alphas RTC is the system timer (running at 1024 Hz). > So changing the interrupt rate from user space wouldn't be a good idea. Then I propose CONFIG_RTC be set to "n" in the arch/alpha files, and the /dev/rtc driver be disabled on alpha. There seems to be confusion on this point in the config files. CONFIG_RTC is for the /dev/rtc driver. Since the timer can only be set to powers of 2, it should be possible to simulate getting the interrupt by calling the rtc.c interrupt handler every 2^n interrupts...that way the user could program the timer for any interval less than 1024 Hz. Cheers, Bob McElrath [Univ. of California at Davis, Department of Physics] --SUOF0GtieIMvvwua Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/rn0EjwioWRGe9K0RAllwAJ9YYERjMwauQOf5QTVWP8ATK3PefQCfWB06 1WduJOqOUT2vSp0nuvk7XTU= =Ov+I -----END PGP SIGNATURE----- --SUOF0GtieIMvvwua--