Date: Wed, 13 May 2009 13:08:23 -0700 From: "Kevin Oberman" <oberman@es.net> To: =?ISO-8859-1?Q?Sylvio_C=E9sar_Teixeira_Amorim?= <scjamorim@bsd.com.br> Cc: freebsd-acpi@freebsd.org Subject: Re: Hi Guys Message-ID: <20090513200823.ECB7F1CC0B@ptavv.es.net> In-Reply-To: Your message of "Wed, 13 May 2009 15:33:42 -0300." <5859850b0905131133l32a43cd2k8eecc695dc175a3a@mail.gmail.com>
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> Date: Wed, 13 May 2009 15:33:42 -0300 > From: =?ISO-8859-1?Q?Sylvio_C=E9sar_Teixeira_Amorim?= <scjamorim@bsd.com.br> > Sender: owner-freebsd-acpi@freebsd.org > > I have one laptop Dell Latitude E4300 with FreeBSD-8-Current, The > temperature of the processor is very high when I'm compiling the kernel, I > get to stay with 88 Celsius, how do I force a download this temperature? Probably the first place to start is to clean the heat sink on your laptop. Simply opening the unit and blowing it out with compressed air can drop CPU temperature by over 10 degrees Celsius. This is probably something that should be done at least annually and more often if the laptop is run in dusty locations, such as sitting on a bed or table covered with a table cloth. It is also possible that the heatsink is not properly attached to the CPU. Several people have reported that cleaning and re-applying heatsink grease greatly improved the temperature. Next, take a look at the values of _PSV and _CRT. (sysctl hw.acpi). If PSV is higher than 88, your system is still within normal operating temperatures. For example, Pentium-M chips are speced to run at a steady temperature of 100C. _PSV on my laptop is 94.5C and _CRT is 99.0C. This means that the system does not start doing anything beyond normal fan cooling until the CPU reaches 94.5C and will reach 99C before starting to shutdown. (This is different from the emergency crowbar shutdown which is for thermal spikes of about 130-150C which might occur when a heatsink becomes dislodged.) When _PSV is reached, the system should simply slow down until the temperature drops. There is hysteresis to keep it from continually cycling. I don't recall numbers, though. If you want to lower the temperature "manually", you can kill powerd (/etc/rc.d/powerd stop) and set the CPU frequency lower. (sysctl dev.cpu.?.freq) where '?' is the CPU number. The available frequencies may be found in sysctl dev.cpu.0.freq_levels. If you are doing the manually, be sure to adjust all CPUs to the same frequency. Finally, placing the system on a surface that leaves an air gap under the system will help, too. Running it on a soft surface inhibits convection cooling and most soft surfaces are pretty goods thermal insulators. -- 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 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
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