Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932318AbWCAFLH (ORCPT ); Wed, 1 Mar 2006 00:11:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932322AbWCAFLH (ORCPT ); Wed, 1 Mar 2006 00:11:07 -0500 Received: from ozlabs.org ([203.10.76.45]:56207 "EHLO ozlabs.org") by vger.kernel.org with ESMTP id S932318AbWCAFLE (ORCPT ); Wed, 1 Mar 2006 00:11:04 -0500 From: Michael Ellerman Reply-To: michael@ellerman.id.au To: Dave Jones Subject: Re: [PATCH] leave APIC code inactive by default on i386 Date: Wed, 1 Mar 2006 16:10:26 +1100 User-Agent: KMail/1.8.3 Cc: "Darrick J. Wong" , linux-kernel@vger.kernel.org, Chris McDermott References: <43D03AF0.3040703@us.ibm.com> <20060301043353.GJ28434@redhat.com> In-Reply-To: <20060301043353.GJ28434@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2433551.HS0gLVgx7B"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200603011610.31090.michael@ellerman.id.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2364 Lines: 59 --nextPart2433551.HS0gLVgx7B Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Wed, 1 Mar 2006 15:33, Dave Jones wrote: > On Wed, Mar 01, 2006 at 02:57:05PM +1100, Michael Ellerman wrote: > > On 1/20/06, Darrick J. Wong wrote: > > > Hi there, > > > > > > Some old i386 systems have flaky APIC hardware that doesn't always > > > work right. Right now, enabling the APIC code in Kconfig means that > > > the APIC code will try to activate the APICs unless 'noapic nolapic' > > > are passed to force them off. The attached patch provides a config > > > option to change that default to keep the APICs off unless specified > > > otherwise, disables get_smp_config if we are not initializing the > > > local APIC, and makes init_apic_mappings not init the IOAPICs if they > > > are disabled. Note that the current behavior is maintained if > > > CONFIG_X86_UP_APIC_DEFAULT_OFF=3Dn. > > > > Did this hit the floor? > > It's still being kicked around. I saw one patch off-list earlier this > week that has some small improvements over the variant originally posted, > but still had 1-2 kinks. Cool. Let's get ironing. I have no idea about the implementation, but the=20 concept is double ++ good as far as I'm concerned. > The number of systems that actually *need* APIC enabled are in the > vast (though growing) minority, so it's unlikely that most newbies > will hit this. The problem is also the inverse of what you describe. > Typically the distros have DMI lists of machines that *need* APIC > to make it enabled by default so everything 'just works'. Ok, even more reason for it to go in. Someone might want to let the folks a= t=20 Ubuntu know too, they seem to have it enabled in their installer kernel. :D cheers --nextPart2433551.HS0gLVgx7B Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBEBSzHdSjSd0sB4dIRAt8JAJwOF3/xlShx1QLvr59TI9syEUbdawCgoXtI TZ9zEqpSv5IjyIQZtP4/U98= =BnAl -----END PGP SIGNATURE----- --nextPart2433551.HS0gLVgx7B-- - 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/