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From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com>
Message-Id: <199510090758.AAA09810@GndRsh.aac.dev.com>
Subject: Re: hangs at Rebooting...
To: joerg_wunsch@uriah.heep.sax.de
Date: Mon, 9 Oct 1995 00:58:44 -0700 (PDT)
Cc: freebsd-current@FreeBSD.org
In-Reply-To: <199510090731.IAA00280@uriah.heep.sax.de> from "J Wunsch" at Oct 9, 95 08:31:49 am
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> 
> As Rodney W. Grimes wrote:
> > 
> > This means your MB is broken such that we have no current way to make
> > it reboot :-(.  It fails the keyboard reset, and fails to detect a
> > CPU shutdown condition :-(.
> 
> Since we are at it:
> 
> Mine fails to reset whenever i'm using the sequence "halt" -> "Hit any
> key..." -> "hit the anykey" -> "partial reset" -> "beep beep beep".
> This is with both methods (kbd controller reset now, CPU shutdown in
> old systems), and it _always_ works for the "reboot" case.  (It
> neither works for things like "call cpu_reset" from DDB.)
> 
> The mainboard is a not-so-recent EISA mainboard, SiS chipset, Phonix
> BIOS.
> 
> The "beep beep beep" seems to indicate that the video controller is
> stuck after the reoboot (and no video memory found).  Any ideas?

Yea, do you happen to have a shared memory ethernet controller sharing
the same 128K byte segment that the video BIOS is in?  Is so I suspect
your ethernet card is left in 8 bit mode and your video bios is 16 bit
mode or vice versa.  This causes a decode problem at POST time, and since
the ISA reset signal was not pulled to reset the cards to there power
on state (probably both 8 bit mode, ethernet unmapped) it hangs the
BIOS.  David did just about everything he could do to the if_ed driver
to fix this `beep beep beep' reboot hang, not much more to be done
other than to move your ethernet shared memory segment.

If that is not it I would need a very complete and nitty gritty detailed
description of the hardware in your system.

Phoenix has never impressed me with there BIOS, it may be a problem there
as well, in that they should firmly bash the video card over the head
before attempting to shadow the bios (infact now that I think about it,
it seems to me that some Phoenix bioses do not reshadow the bios on a
CPU shutdown, this can leave trash in shadow ram, but FreeBSD should not
be mucking with that area, but there was a virus attack that used this
little known tid bit to hide it self.)

It might help to poke the warm/cold boot flag location at 0x472 back
to zero during cpu_reset.  See sys/i386/i386/locore.s, very first thing
FreeBSD does is to set the BIOS warm/cold flag to warm.  Search for
``warm boot'' or ``btext''.

-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                 Reliable computers for FreeBSD