Subject: Re: Gateway 2000 keyboard vs ddb
To: Charles M. Hannum <mycroft@ai.mit.edu>
From: Hellmuth Michaelis <hm@hcswork.hcs.de>
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
--
Hellmuth Michaelis GFKT HCS Computertechnik GmbH Hamburg, Europe
We all live in a yellow subroutine, yellow subroutine ...