Subject: netbsd and the 8254 timer (i386) was: Re: IDT Winchip C6 - broken TSC, slow system clock
To: None <firstname.lastname@example.org>
From: Clint Wunderlich <email@example.com>
Date: 06/25/2001 09:38:39
How or when does netbsd initialize (or RE-initialize) the 8254?
The behavior after the clock slows down is consistent with the 8254 being
set to a slower interrupt rate (higher divisor); the time is slow, and beeps
through the PC speaker are long.
Can mp3 players (amp, mpg123) or sound card drivers (soundblaster) make a
call through the kernel to change the 8254 speed, or could they do it
directly? (and why would they?)
Is there any way I can debug this, or catch who sends commands to the 8254,
which looks to be at address 0x97?
----- Original Message -----
From: "Jason R Thorpe" <firstname.lastname@example.org>
To: "cpctc" <email@example.com>
Sent: Saturday, June 23, 2001 3:27 AM
Subject: Re: IDT Winchip C6 - broken TSC, slow system clock
> On Fri, Jun 22, 2001 at 10:07:57PM -0400, cpctc wrote:
> > I've searched for info on this; freebsd allows the following command:
> > sysctrl -w kern.timecounter.hardware=i8254
> > .. which should ignore the broken TSC register and use the i8254 chip
> > keeping time.
> > I haven't found a way to do this in netbsd, however the kernel already
> > the TSC feature is no good, so why am I having this problem?
> NetBSD doesn't use the TSC for keeping time, it only uses the 8254 timer.
> -- Jason R. Thorpe <firstname.lastname@example.org>