From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932453AbWF3VIW (ORCPT ); Fri, 30 Jun 2006 17:08:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932399AbWF3VIW (ORCPT ); Fri, 30 Jun 2006 17:08:22 -0400 Received: from sj-iport-1-in.cisco.com ([171.71.176.70]:4631 "EHLO sj-iport-1.cisco.com") by vger.kernel.org with ESMTP id S932420AbWF3VIV (ORCPT ); Fri, 30 Jun 2006 17:08:21 -0400 To: Andrew Morton Cc: "Bryan O'Sullivan" , mst@mellanox.co.il, openib-general@openib.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 28 of 39] IB/ipath - Fixes a bug where our delay for EEPROM no longer works due to compiler reordering X-Message-Flag: Warning: May contain useful information References: <5f3c0b2d446d78e3327f.1151617279@eng-12.pathscale.com> <20060629170711.757a97d2.akpm@osdl.org> From: Roland Dreier Date: Fri, 30 Jun 2006 14:08:19 -0700 In-Reply-To: <20060629170711.757a97d2.akpm@osdl.org> (Andrew Morton's message of "Thu, 29 Jun 2006 17:07:11 -0700") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) XEmacs/21.4.18 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 30 Jun 2006 21:08:20.0135 (UTC) FILETIME=[507B5370:01C69C89] Authentication-Results: sj-dkim-2.cisco.com; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com verified; ); Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > static void i2c_wait_for_writes(struct ipath_devdata *dd) > > { > > + mb(); > > (void)ipath_read_kreg32(dd, dd->ipath_kregs->kr_scratch); > > } > That's a bit weird. I wouldn't have expected the compiler to muck around > with a readl(). I never liked this patch. The last time it came up there were conflicting answers about whether it was a code generation bug or a real issue talking to hardware or what. At the least I think this merits a big comment explain what's going on -- and even better would be really understanding the bug that's being fixed so that we're confident it is indeed a real fix. - R.