From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751822Ab1GSLTp (ORCPT ); Tue, 19 Jul 2011 07:19:45 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:57045 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751032Ab1GSLTo (ORCPT ); Tue, 19 Jul 2011 07:19:44 -0400 Date: Tue, 19 Jul 2011 12:19:34 +0100 From: Matthew Garrett To: Jan Beulich Cc: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: serialize EFI time accesses on rtc_lock Message-ID: <20110719111933.GA13122@srcf.ucam.org> References: <4E257E33020000780004E319@nat28.tlf.novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E257E33020000780004E319@nat28.tlf.novell.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 19, 2011 at 11:53:07AM +0100, Jan Beulich wrote: > The EFI specification requires that callers of the time related runtime > functions serialize with other CMOS accesses in the kernel, as the EFI > time functions may choose to also use the legacy CMOS RTC. > > Besides fixing a latent bug, this is a prerequisite to safely enable > the rtc-efi driver for x86, which ought to be preferred over rtc-cmos > on all EFI platforms. ACK in principle, although I've just merged this and the IA64 code together which makes that more awkward. I can fix it up, though. -- Matthew Garrett | mjg59@srcf.ucam.org