Return-path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:39008 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751245Ab0J2A57 convert rfc822-to-8bit (ORCPT ); Thu, 28 Oct 2010 20:57:59 -0400 Received: by iwn10 with SMTP id 10so2964946iwn.19 for ; Thu, 28 Oct 2010 17:57:59 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <4CCA0B26.5010008@openwrt.org> References: <20101005131744.GB4074@tuxdriver.com> <20101005195039.GD11831@tux> <4CB0890D.3050208@openwrt.org> <4CCA0908.6000105@candelatech.com> <4CCA0B26.5010008@openwrt.org> From: "Luis R. Rodriguez" Date: Thu, 28 Oct 2010 17:57:37 -0700 Message-ID: Subject: Re: [ath9k-devel] [RFC] ath9k: Insert wmb before linking dma descriptors To: Felix Fietkau Cc: Ben Greear , linux-wireless , "John W. Linville" , "ath9k-devel@venema.h4ckr.net" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, Oct 28, 2010 at 4:45 PM, Felix Fietkau wrote: > On 2010-10-29 1:36 AM, Ben Greear wrote: >> On 10/09/2010 08:23 AM, Felix Fietkau wrote: >>> On 2010-10-09 5:19 PM, Björn Smedman wrote: >>>> On Tue, Oct 5, 2010 at 9:50 PM, Luis R. Rodriguez >>>>  wrote: >>>>> Felix is more familiar with this area so I'll let him chime with >>>>> his ACK/NACK. >>>>> >>>>>   Luis >>>> >>>> So Felix, what do you think? I realize it may not be a common problem >>>> on any currently popular platform, but don't you agree it is in >>>> principle unsafe to write to the ds_link field of dma descriptors >>>> without a guarantee that those writes will be performed in the >>>> intended order? >>> Haven't had time to review this in detail yet. I'll take another look at >>> it later... >> >> Had a chance to look at it?  I've been carrying this in my >> tree and it hasn't caused any obvious problems, for what that's >> worth... > Not sure if the patch helps with anything, but I think it can go in... I'd rather not add it if its not fixing anything. I hate code that is there just because we have a fuzzy feeling it helps. So NACK unless it fixes something. Luis