Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750794AbWIAUoI (ORCPT ); Fri, 1 Sep 2006 16:44:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750763AbWIAUoI (ORCPT ); Fri, 1 Sep 2006 16:44:08 -0400 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:37387 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S1750794AbWIAUoG (ORCPT ); Fri, 1 Sep 2006 16:44:06 -0400 Date: Fri, 1 Sep 2006 21:43:43 +0100 From: Russell King To: Andrew Morton Cc: Roland Dreier , Adrian Bunk , Tom Tucker , Steve Wise , Roland Dreier , linux-kernel@vger.kernel.org, openib-general@openib.org, "David S. Miller" Subject: Re: 2.6.18-rc5-mm1: drivers/infiniband/hw/amso1100/c2.c compile error Message-ID: <20060901204343.GA4979@flint.arm.linux.org.uk> Mail-Followup-To: Andrew Morton , Roland Dreier , Adrian Bunk , Tom Tucker , Steve Wise , Roland Dreier , linux-kernel@vger.kernel.org, openib-general@openib.org, "David S. Miller" References: <20060901015818.42767813.akpm@osdl.org> <20060901160023.GB18276@stusta.de> <20060901101340.962150cb.akpm@osdl.org> <20060901112312.5ff0dd8d.akpm@osdl.org> <20060901130444.48f19457.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060901130444.48f19457.akpm@osdl.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1648 Lines: 40 On Fri, Sep 01, 2006 at 01:04:44PM -0700, Andrew Morton wrote: > On Fri, 01 Sep 2006 12:53:47 -0700 > Roland Dreier wrote: > > Yes, I agree that's a good plan, especially the documentation part. > > However I would argue that what's in drivers/infiniband/hw/mthca/mthca_doorbell.h > > is legitimate: the driver uses __raw_writeq() when it exists and uses > > two __raw_writel()s properly serialized with a device-specific lock to > > get exactly the atomicity it needs on 32-bit archs. > > No, driver-specific workarounds are not legitimate, sorry. > > The driver should simply fail to compile on architectures which do not > implement __raw_writeq(). So, what you're basically saying is that on architectures which can _NOT_ implement an atomic __raw_writeq(), certain drivers simply will not be available? > We can speed up the process by sending helpful emails to architecture > maintainers, but they'll notice either way. I think you're completely wrong in the context of the message you're replying to - it's talking about an _atomic_ 64-bit write. Sure, if you want a _non-atomic_ 64-bit write then that's possible, but many 32-bit architectures can't do a 64-bit atomic IO write and that isn't something they can "fix". -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core -- VGER BF report: H 5.55112e-17 - 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/