Date: Tue, 01 Mar 2005 11:03:43 -0800 From: Nate Lawson <nate@root.org> To: Bruno Ducrot <ducrot@poupinou.org> Cc: Joe Holden <joe@resync.eclipse.co.uk> Subject: Re: Laptop And ACPI Message-ID: <4224BC8F.7060501@root.org> In-Reply-To: <20050301080018.GA17731@poupinou.org> References: <20050301025549.84FC02E2D8B@mra03.ex.eclipse.net.uk> <20050301080018.GA17731@poupinou.org>
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Bruno Ducrot wrote: > 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. Thanks, Bruno. Just another note that you should be able to put the timecounter choice in /boot/loader.conf too I think. -- Nate
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