Date: Wed, 01 Dec 2004 10:44:41 -0800 From: "Kevin Oberman" <oberman@es.net> To: "Wilkinson, Alex" <alex.wilkinson@dsto.defence.gov.au> Cc: freebsd-acpi@freebsd.org Subject: Re: ACPI differences 4.10 - 5.3, laptop problem Message-ID: <20041201184441.220185D04@ptavv.es.net> In-Reply-To: Your message of "Wed, 01 Dec 2004 10:07:00 %2B1030." <20041130233659.GC20263@squash.dsto.defence.gov.au>
next in thread | previous in thread | raw e-mail | index | archive | help
> Date: Wed, 1 Dec 2004 10:07:00 +1030 > From: "Wilkinson, Alex" <alex.wilkinson@dsto.defence.gov.au> > Sender: owner-freebsd-acpi@freebsd.org > > 0n Tue, Nov 30, 2004 at 10:05:46AM -0800, Kevin Oberman wrote: > > > Looks like the same processor I have and you can try adding: > > options CPU_ENABLE_TCC > > to your kernel. This enables the P4 Thermal Control which will let you > > throttle the speed of the CPU without ACPI. Use the hw.p4tcc sysctls to > > manage the speed. > > Kevin, why don't you use 'C states' for the afforementioned ? > Throttling reduces CPU performance. I thought it would be better to > use C1,C2,C3, states. Or does fbsd ACPI not support C states yet ? C states are used in ACPI, but they provide minimal reduction in power consumption, This is especially true if you have USB drivers present as they block ever getting to C3. ACPI does support CPU throttling, but this is not too different from the TCC throttling. (NOTE: TCC and ACPI CPU throttles are independent. Setting TCC to 13% and the ACPI throttle to 4 results in about 6% of full speed. This is just a bit painful!) In any case, the issue was rapid battery drain when ACPI was not present and TCC is not dependent on ACPI. It's always there for P4s. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20041201184441.220185D04>