From owner-freebsd-stable@FreeBSD.ORG Mon Oct 27 16:18:11 2008 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 3D41A106567B for ; Mon, 27 Oct 2008 16:18:11 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from QMTA01.westchester.pa.mail.comcast.net (qmta01.westchester.pa.mail.comcast.net [76.96.62.16]) by mx1.freebsd.org (Postfix) with ESMTP id 8D12D8FC4C for ; Mon, 27 Oct 2008 16:18:08 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from OMTA12.westchester.pa.mail.comcast.net ([76.96.62.44]) by QMTA01.westchester.pa.mail.comcast.net with comcast id XqPF1a00X0xGWP851sJ8Al; Mon, 27 Oct 2008 16:18:08 +0000 Received: from koitsu.dyndns.org ([69.181.141.110]) by OMTA12.westchester.pa.mail.comcast.net with comcast id XsJ61a00K2P6wsM3YsJ7yT; Mon, 27 Oct 2008 16:18:08 +0000 X-Authority-Analysis: v=1.0 c=1 a=j1jtvhf0zA8A:10 a=T4SDRHG4orYA:10 a=QycZ5dHgAAAA:8 a=gtLclbzq4LdMaKvm740A:9 a=y5jnm3NcaIDNIJa3F4EA:7 a=ULynrNWdqBSmK_4fLfAHhR5Q4PcA:4 a=EoioJ0NPDVgA:10 a=LY0hPdMaydYA:10 Received: by icarus.home.lan (Postfix, from userid 1000) id 88098C941E; Mon, 27 Oct 2008 09:18:06 -0700 (PDT) Date: Mon, 27 Oct 2008 09:18:06 -0700 From: Jeremy Chadwick To: John Baldwin Message-ID: <20081027161806.GA25404@icarus.home.lan> References: <20081025014218.GA47549@phat.za.net> <20081025080945.GA55413@icarus.home.lan> <200810271157.06096.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200810271157.06096.jhb@freebsd.org> User-Agent: Mutt/1.5.18 (2008-05-17) Cc: Jo Rhett , Aragon Gouveia , freebsd-stable Stable Subject: Re: 6.4 RC1 locks up solid on first reboot 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, 27 Oct 2008 16:18:11 -0000 On Mon, Oct 27, 2008 at 11:57:05AM -0400, John Baldwin wrote: > On Saturday 25 October 2008 04:09:45 am Jeremy Chadwick wrote: > > Just for posterity: the USB Legacy Support BIOS option does not affect > > natively-connected PS/2 keyboards; you can leave the option enabled even > > in the scenario where you have a USB keyboard *and* a PS/2 keyboard > > plugged in; one will not "trump" the other. Instead, you should have > > two keyboards which function in OSes/environments which lack a USB > > stack. (That is, until something resets/reassigns the BIOS-controlled > > interrupt, which will then break USB->PS/2 emulation; the native PS/2 > > keyboard should not be affected by this) > > This last statement is not quite true (at least not always true). For many > systems, the way the PS/2 emulation works is that accesses to the backing I/O > ports (0x60 and 0x64) case a trap into SMM and the SMI handler in the BIOS > then talks to the USB controller and keyboard and updates the register values > to simulate the I/O port accesses. This is disabled by having the USB host > controller driver frob flags in controller registers to disable the SMI > traps. Thanks for cluing me in, John. I'm used to legacy device emulation being done purely from an interrupt handler point of view (BIOS mapping code to a specific interrupt), and wasn't even aware of SMM/SMI. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |