Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261998AbUCaPDs (ORCPT ); Wed, 31 Mar 2004 10:03:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262002AbUCaPDs (ORCPT ); Wed, 31 Mar 2004 10:03:48 -0500 Received: from mail.shareable.org ([81.29.64.88]:29844 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S261998AbUCaPDr (ORCPT ); Wed, 31 Mar 2004 10:03:47 -0500 Date: Wed, 31 Mar 2004 16:02:19 +0100 From: Jamie Lokier To: "Maciej W. Rozycki" Cc: Bill Davidsen , Len Brown , Chris Friesen , Willy Tarreau , "Richard B. Johnson" , Alan Cox , Arkadiusz Miskiewicz , Marcelo Tosatti , Linux Kernel Mailing List , ACPI Developers Subject: Re: [ACPI] Re: Linux 2.4.26-rc1 (cmpxchg vs 80386 build) Message-ID: <20040331150219.GC18990@mail.shareable.org> References: <4069A359.7040908@nortelnetworks.com> <1080668673.989.106.camel@dhcppc4> <4069D3D2.2020402@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 679 Lines: 19 Maciej W. Rozycki wrote: > Well, "cmpxchg", "xadd", etc. can be easily emulated with an aid of a > spinlock. With SMP operation included. Nope. Len Brown wrote: > Linux uses this locking mechanism to coordinate shared access > to hardware registers with embedded controllers, > which is true also on uniprocessors too. You can't do that with a spinlock. The embedded controllers would need to know about the spinlock. -- Jamie - 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/