The watchdog is disabled by writes to port 0x80. which may be a
good/convenient thing for the BIOS, as Roger noted; it ensures the WD is
disabled during startup. However, i need it enabled without worry that
some part of the kernel is going to disable it accidently.
I would expect the same delay to be produced by reading the port, i.e.
changing the "outb" to "inb". This (hopefully) will have no effect on
the WD while still providing the requested delay to kernel callers.
Changing the hardware WD, as some of you suggested, is not an option.
This is an off-the-shelf SBC (not my design), and not suited to
resoldering.
-----Original Message-----
From: R.E.Wolff@BitWizard.nl [mailto:R.E.Wolff@BitWizard.nl]
Sent: Tuesday, March 16, 1999 3:11 AM
To: root@chaos.analogic.com
Cc: tim.wall@pinpointco.com; linux-kernel@vger.rutgers.edu
Subject: Re: ioport conflict with "dma page reg" (0x80)
Richard B. Johnson wrote:
> On Mon, 15 Mar 1999, Wall, Tim wrote:
>
> > I have a single-board computer with a hardware watchdog which uses
I/O
> > addresses 0x80, 0x443, and 0x444.
> >
> > The problem is that something else in the system is writing to 0x80,
> > which resets/disables the watchdog.
> >
>
> 0x80 is the manufacturing test port. If you have a watchdog that
> cares about that, it's broken. The kernel didn't reserve it, the
> AT-Class hardware did. In fact during POST, you can read numbers
> written to that port to see how far a, possibly defective, board
> has gotten upon power up.
But, using port 0x80 to keep the watchdog from activating is a good
way of making sure that the system comes through the POST before the
watchdog kicks in....
Read Alans reply for the hint on how to get along.
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* * Never blow in a cat's ear because if you do, usually after three or * * four times, they will bite your lips! And they don't let go for at * * least a minute. -- Lisa Coburn, age 9- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/