From owner-freebsd-stable@FreeBSD.ORG Mon Jul 12 12:51:54 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BEF7F1065673 for ; Mon, 12 Jul 2010 12:51:54 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 8F6AE8FC14 for ; Mon, 12 Jul 2010 12:51:54 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 3EA3246B03; Mon, 12 Jul 2010 08:51:54 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 387158A04E; Mon, 12 Jul 2010 08:51:53 -0400 (EDT) From: John Baldwin To: freebsd-stable@freebsd.org Date: Mon, 12 Jul 2010 08:40:30 -0400 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20100217; KDE/4.4.5; amd64; ; ) References: <6B57591F-9FA2-45EB-825F-1DB025C0635D@hostpoint.ch> <201007091603.31843.jhb@freebsd.org> <08562D52-02AA-46CF-BFCD-00D0A3C4DC34@hostpoint.ch> In-Reply-To: <08562D52-02AA-46CF-BFCD-00D0A3C4DC34@hostpoint.ch> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201007120840.30966.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Mon, 12 Jul 2010 08:51:53 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Markus Gebert Subject: Re: 8.1-RC2 - PCI fatal error or MCE triggered by USB/ehci on Sun X4100M2? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Jul 2010 12:51:54 -0000 On Friday, July 09, 2010 7:53:39 pm Markus Gebert wrote: > > I'm curious if disabling USB legacy support in the BIOS causes it to still die > > even with ehci not loaded. If so, then the SMI# for the ehci controller must > > somehow prevent the issue, perhaps by triggering frequently enough to slow the > > rate of I/O requests down? > > > I disabled usb legacy support in the BIOS and booted a kernel with usb+ohci+ukbd+ums but without ehci. Unfortunately, I cannot reproduce the MCE. Ok, that kills that theory then. > Just to get you right: your theory is that when we don't load the ehci driver, then the ehci-controller isn't taken over during boot and therefore handled through SMM so that SMIs might occur often enough to throttle the system just enough to not let the problem appear? I'm not very familiar with usb legacy support and SMM, but why would ehci be handled through SMM when the only usb devices (the virtual keyboard and mouse) actually sit on ohci? And why would disabling legacy support help getting more SMIs to throttle the system? As I unterstand this, and I might be terribly wrong, legacy support is what would cause SMIs in the first place. 1) Yes. 2) Many of the legacy USB emulations are very dumb and are polled rather than interrupt driven. Thus, if legacy USB support is enabled, then a timer kicks off an SMI# every so often (at least once a second on some machines, perhaps even more frequent) that polls the USB bus for any device attach/detach events. I think it might also poll attached keyboards that way as well. 3) I thought that disabling legacy USB but _not_ loading ehci would case it to break the same way that loading ehci causes it to break as it would turn off the SMI#'s that loading ehci also disables. -- John Baldwin