From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261434AbVFAPgz (ORCPT ); Wed, 1 Jun 2005 11:36:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261419AbVFAPgy (ORCPT ); Wed, 1 Jun 2005 11:36:54 -0400 Received: from mail.timesys.com ([65.117.135.102]:52965 "EHLO exchange.timesys.com") by vger.kernel.org with ESMTP id S261434AbVFAPff (ORCPT ); Wed, 1 Jun 2005 11:35:35 -0400 Message-ID: <429DD553.3080509@timesys.com> Date: Wed, 01 Jun 2005 11:33:39 -0400 From: john cooper User-Agent: Mozilla Thunderbird 0.8 (X11/20040913) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrea Arcangeli CC: Paulo Marques , Ingo Molnar , "Paul E. McKenney" , Esben Nielsen , James Bruce , Nick Piggin , "Bill Huey (hui)" , Andi Kleen , Sven-Thorsten Dietrich , dwalker@mvista.com, hch@infradead.org, akpm@osdl.org, linux-kernel@vger.kernel.org, john cooper Subject: Re: RT patch acceptance References: <20050531161157.GQ5413@g5.random> <20050531183627.GA1880@us.ibm.com> <20050531204544.GU5413@g5.random> <429DA7AE.5000304@grupopie.com> <20050601135154.GF5413@g5.random> <20050601141919.GA9282@elte.hu> <20050601143202.GI5413@g5.random> <20050601144612.GJ5413@g5.random> <429DCD25.3010800@grupopie.com> <20050601151701.GM5413@g5.random> In-Reply-To: <20050601151701.GM5413@g5.random> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 01 Jun 2005 15:28:48.0562 (UTC) FILETIME=[9B527920:01C566BE] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli wrote: > The reason I raise this topic is that the fact spin_lock_irq wasn't > disabling irqs like it does in the non-RT configuration, sounded like > the technique described in the patent and it's one technique I always > considered not-usable. I possibly wrongly remembered that redefining the > disable-interrupt operation not to disable irqs, was the crucial point > of the patent. But as I've said I'm not a lawyer and so I may have > misunderstood completely the technique that the rtlinux patent is > covering (the way patents are written is not very readable to me). FWIW the decoupling of interrupt mask levels from spinlocks is a technique which predates the patent under discussion by a decade or so. And yes IANAL as well but it seems the patent would/should not have been awarded if it conflicted/overlapped with preexisting usage. I'd hazard this is a non-issue. -john -- john.cooper@timesys.com