Return-path: Received: from mail-ia0-f174.google.com ([209.85.210.174]:50876 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751758Ab2LCQTc (ORCPT ); Mon, 3 Dec 2012 11:19:32 -0500 Received: by mail-ia0-f174.google.com with SMTP id y25so2275379iay.19 for ; Mon, 03 Dec 2012 08:19:32 -0800 (PST) Message-ID: <50BCD110.6050803@lwfinger.net> (sfid-20121203_171936_244331_4B1E99D6) Date: Mon, 03 Dec 2012 10:19:28 -0600 From: Larry Finger MIME-Version: 1.0 To: Nathan Hintz CC: linux-wireless@vger.kernel.org Subject: Re: brcmsmac: Data bus error in reading tsf_random References: <50BAB095.2070103@hauke-m.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/02/2012 10:47 PM, Nathan Hintz wrote: > I encountered a similar DBE using the "broadcom-wl" driver (OpenWRT) on a > Linksys E3000; except that it occurred when reading "ifs_ctl" (offset 0x688). > I too tried putting in some printk's (in linux_osl.c), which caused the > problem to go away. I eventually found that doing a dummy read of 4 bytes > at that particular address just prior to the actual two byte read caused > the problem to go away as well (an ugly hack). I can reproduce it if you > want a stack trace. Does an ndelay(xx), with xx of 10 or so, be as effective as the dummy read? It is not a lot less of a hack, but it would indicate the source of the problem. Larry