Subject: Re: Gateway 2000 keyboard vs ddb
To: Charles M. Hannum <>
From: Hellmuth Michaelis <>
List: port-i386
Date: 03/21/1995 21:03:17
>From the keyboard of Charles M. Hannum:

> I used to use `delay(6)' in pccons, because that's what someone
> recommended, and it seemed to fix the problem of the keyboard always
> hanging on boot on Gateway machines.

Same for pcvt, the delay(6) was added because someone found out that this
reproducably fixed his problems with a Gateway 2000 machine/keyboard.

> However, delay() isn't really accurate for values that small.  I'd
> suggest instead changing it to something like pccons now uses:
> #define	KBD_DELAY \
> 	{ u_char x = inb(0x84); } \
> 	{ u_char x = inb(0x84); } \
> 	{ u_char x = inb(0x84); } \
> 	{ u_char x = inb(0x84); }
> If the 7us timing requirement is correct, then you may need as many as
> 6 inb()s.

Charles, what about 200 MHz clocked pentiums ? :-(

Is the time inb's from port 0x84 last constant by design/agreement/hardware ?

If not, is there a way or an idea how to get processor/speed independent
delays of such small values ?

Hellmuth Michaelis        GFKT HCS Computertechnik GmbH        Hamburg, Europe
                     We all live in a yellow subroutine, yellow subroutine ...