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Date:      Tue, 1 Mar 2005 09:00:18 +0100
From:      Bruno Ducrot <ducrot@poupinou.org>
To:        Joe Holden <joe@resync.eclipse.co.uk>
Cc:        freebsd-acpi@freebsd.org
Subject:   Re: Laptop And ACPI
Message-ID:  <20050301080018.GA17731@poupinou.org>
In-Reply-To: <20050301025549.84FC02E2D8B@mra03.ex.eclipse.net.uk>
References:  <20050301025549.84FC02E2D8B@mra03.ex.eclipse.net.uk>

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On Tue, Mar 01, 2005 at 03:03:40AM -0000, Joe Holden wrote:
> Hi, i'm having issues with a 4 year or so old laptop, if I disable acpi, the
> CPU is reported at 168 MHz and the clock tends to jump about abit.
> 
>  
> 
> It's a Pentium 3 650 MHz

The TSC of PIII is more or less broken if using speedstep or apm idle
call.  Its also unreliable when the processor is going to SMM (which
happens often IIRC on laptops when APM is enabled)

With ACPI, FreeBSD use another time counter (acpi_timer) by
default and not TSC so you don't have this issue.

You should use another time counter (its in a FAQ IIRC).

Example:

root@poupon.echo-net.net [8:47] ~# sysctl kern.timecounter.choice
kern.timecounter.choice: TSC(800) ACPI-fast(1000) i8254(0) dummy(-1000000)
root@poupon.echo-net.net [8:47] ~# sysctl kern.timecounter.hardware=i8254

If i8254 is correct, then use it.

> 
> With speed step, which I *think* is causing the issues.

Not only, there is problem when calling apm idle call aswell.

> With ACPI enabled, it hangs at Mounting NFS Partitions, after devd etc,
> although I don't have any nfs mounts.
> 
> Without ACPI enabled, it boots with the lower clock speed being reported,
> and intermittent clock jumps, which is causing me to have ntpdate running on
> a 60 second cron.
> 
>  
> 
> However, I'm not entirely sure the laptop supports acpi, as I experienced no
> issues on FreeBsd 4.x, however, it's now running 5.3-STABLE (7 day old
> cvsup).

There are lots of issues with ACPI and older laptops.  If I were you and
if I were happy with APM, then I would use APM, and I would put in
/etc/sysctl.conf

a line like:
kern.timecounter.hardware=i8254


> If anyone could shed some light on this as to what I could do to correct it,
> or some sort of patch, other than updating the bios, as that isn't possible
> due to the lack of a working floppy drive, that would be great.

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.



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