From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH] s2io ppc64 fix for readq/writeq Date: Mon, 06 Nov 2006 19:52:58 +1100 Message-ID: <1162803178.28571.300.camel@localhost.localdomain> References: <1162780109.28571.273.camel@localhost.localdomain> <454EE943.6000603@pobox.com> <1162800248.28571.296.camel@localhost.localdomain> <454EF07B.4010503@pobox.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Linus Torvalds Return-path: Received: from gate.crashing.org ([63.228.1.57]:58008 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1423624AbWKFIyO (ORCPT ); Mon, 6 Nov 2006 03:54:14 -0500 To: Jeff Garzik In-Reply-To: <454EF07B.4010503@pobox.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > This is why I said "good enough for drivers". This is _key_. > > I have run into several [PCI] devices with 64-bit registers, and > __none__ of them had requirements such that the Linux platform code > -must- provide an atomic readq/writeq. Probably because everybody wants > to support 32-bit platforms with their devices. > > What you call "fairly bogus" is precisely what drivers need. These > devices with 64-bit registers just don't need the atomicity that arch > developers harp about :) Is there any consistency in that case in which half need to be read/written first ? Or none of these ever had side effects ? Ben.