Return-path: Received: from mail-oa0-f45.google.com ([209.85.219.45]:57898 "EHLO mail-oa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752173Ab3COGhm convert rfc822-to-8bit (ORCPT ); Fri, 15 Mar 2013 02:37:42 -0400 Received: by mail-oa0-f45.google.com with SMTP id o6so3094684oag.18 for ; Thu, 14 Mar 2013 23:37:41 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <51421afb.xUa3KbaBuvmUk4RG%Larry.Finger@lwfinger.net> Date: Fri, 15 Mar 2013 07:37:41 +0100 Message-ID: (sfid-20130315_073754_385411_26CF9C16) Subject: Re: [RFC/RFT] b43: A fix for DMA transmission sequence errors From: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= To: Larry Finger Cc: Michael Buesch , isedev@gmail.com, b43-dev@lists.infradead.org, linux-wireless@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: 2013/3/14 Rafał Miłecki : > 2013/3/14 Larry Finger : >> From: Iestyn C. Elfick >> >> Intermittently, b43 will report "Out of order TX status report on DMA ring". >> When this happens, the driver must be reset before communication can resume. >> The cause of the problem is believed to be an error in the closed-source >> firmware; however, all versions of the firmware are affected. >> >> This change uses the observation that the expected status is always 2 less >> than the observed value, and supplies a fake status report to skip one >> header/data pair. >> >> Signed-off-by: Larry Finger >> Cc: Stable >> --- >> >> Although this is a hack, it seems to work for the OP. It should not cause any >> ill effects on any device that does not have the problem. >> >> It does need a lot more testing, particularly on systems prone to the out-of-order >> status report problem. >> >> If anyone can think of a cleaner, less intrusive solution, please let us know. > > I wonder if this is hardware supporting unaligned access with > full-addressing for DMA engine. Maybe it support index-based indexes > for backward compatibility only, and it's somehow broken? > > Can we test full-addressing first? I'll try to prepare a patch for > this during the weekend. OK, so after early tests, this card doesn't support full-addressing at all. I'll give this patch a try during the weekend. -- Rafał