https://www.thinkwiki.org/w/api.php?action=feedcontributions&feedformat=atom&user=Dhruv 2026-04-23T06:36:10Z User contributions MediaWiki 1.31.12 https://www.thinkwiki.org/w/index.php?title=Laptop-mode&diff=30635 2007-06-24T02:53:43Z

<p>Dhruv: Added info on ubuntu laptop-mode</p> <hr /> <div>An often overlooked feature in 2.4.23+ and 2.6.6+ Linux kernels is the laptop-mode. It may be activated by writing a &quot;5&quot; into {{path|/proc/sys/vm/laptop_mode}}. Laptop-mode, when configured correctly, can make the kernel buffer disk activities for quite a long time and keep the harddisk spun down for most of the time to save power.<br /> <br /> There is also a set of userland tools made to automatically manage all aspects of laptop-mode configuration according to the actual mode of operation (ac/battery-status). It is called [[laptop-mode-tools]] and you can install it in debian via apt-get or download it from [http://www.xs4all.nl/~bsamwel/laptop_mode/tools here].<br /> <br /> Almost anything you need to know about laptop-mode can be read in your Linux kernel documentation at /usr/src/linux/Documentation/laptop-mode.txt&lt;br&gt;<br /> If you can not find this file on your laptop, then go and get yourself the latest kernel sources.<br /> <br /> {{NOTE|The use of Laptop-mode and laptop-mode-tools is not recommended in SuSE Linux. The supplied &lt;tt&gt;powersaved&lt;/tt&gt; already takes care of everything regarding power saving}}<br /> {{NOTE| Laptop-mode is disabled by default on Ubuntu 6.10 and later. See [http://samwel.tk/laptop_mode/packages/ubuntu here] for more details}}. <br /> <br /> <br /> === Keeping the disk in the stand-by state ===<br /> <br /> Laptop-mode is only effective if one avoids spinning up the disk for frivoulous reasons. What will spin a disk up is dependent on the HD firmware, but unfortunately most will spin up on just about every command. To add insult to injury, ATA/SATA pass-through commands are not logged through the {{path|/proc/sys/vm/block_dump}} facility, and thus invisible to tools like '''lm-profiler'''.<br /> <br /> {{HINT|The '''lm-profiler''' tool from laptop-mode-tools can be used to list all processes doing normal disk access.}}<br /> <br /> In systems where the HD spins up too easily, the &quot;'''hddtemp'''&quot; daemon will wake up the disk every minute, and must thus be disabled for power management to be effective. The &quot;'''smartd'''&quot; daemon is also an offender, but fortunately its default configuration issues commands to the HDs only every 30 minutes.<br /> <br /> {{HINT|smartd can be configured to never issue commands to the disk if it is in the sleep or standby states, through the use of option &quot;'''-n standby,q'''&quot;. The &quot;''',q'''&quot; is needed to supress syslog messages.}}<br /> <br /> [[Category:Glossary]]</div>

Dhruv