From owner-freebsd-hackers Sat Mar 6 16: 0:55 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from st-lcremean.tidalwave.net (host-e186.tidalwave.net [208.213.203.186]) by hub.freebsd.org (Postfix) with ESMTP id 6D60915126 for ; Sat, 6 Mar 1999 16:00:49 -0800 (PST) (envelope-from lee@st-lcremean.tidalwave.net) Received: (from lee@localhost) by st-lcremean.tidalwave.net (8.9.2/8.9.2) id TAA85234; Sat, 6 Mar 1999 19:00:05 -0500 (EST) (envelope-from lee) Message-ID: <19990306190005.A85183@tidalwave.net> Date: Sat, 6 Mar 1999 19:00:05 -0500 From: Lee Cremeans To: Mike Smith , Sheldon Hearn Cc: hackers@FreeBSD.ORG Subject: Re: BIOS reboot question from Linux user Reply-To: lcremean@tidalwave.net References: <33057.920541508@axl.noc.iafrica.com> <199903062324.PAA00691@dingo.cdrom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.2i In-Reply-To: <199903062324.PAA00691@dingo.cdrom.com>; from Mike Smith on Sat, Mar 06, 1999 at 03:24:50PM -0800 X-OS: FreeBSD 3.0-STABLE Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, Mar 06, 1999 at 03:24:50PM -0800, Mike Smith wrote: > > > > Hi folks, > > > > The following question is cluttering up the GNATS database (misc/5552): > > > > | I found out today that the Linux parameter of append reboot=bios > > | (which passes the reboot=bios) is unavailable under FreeBSD. Is this > > | correct? The keyboard fix in the kernel does not fix my problem, and > > | the machine still does not reboot. > > | > > | Is there a way to tell the machine to reboot via the bios? > > > > I don't understand what this chap's talking about and wondered if anyone > > here with an understanding of how the referenced Linux option works. > > > > Does reboot(8) use the BIOS code for rebooting? > > No. > > There are arguments for and against trying; currently the only systems > that would benefit from such an option are those with broken hardware. To clarify, FreeBSD first tries to reset the computer using the keyboard controller (which is the original AT-compatible way of doing it). Some machines, however, don't have the RST# line from the CPU connected to the controller. In this case, FreeBSD resets the machine by unmapping all of memory space, which triple-faults the processor, putting it into the SHUTDOWN state. The chipset on the motherboard is supposed to convert this to a hard reset, and if it doesn't, well, it's bogus -- you're not fully AT-compatible if this doesn't work. All this is in /sys/i386/i386/vm_machdep.c if you want a look. -- +--------------------------------------------------------------------+ | Lee Cremeans -- Manassas, VA, USA (WakkyMouse on DALnet and WTnet)| | lcremean@tidalwave.net| http://st-lcremean.tidalwave.net/~lee | To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message