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Old 08-07-10, 12:15 PM   #1
cedricv
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Join Date: May 2010
Posts: 19
Exclamation Powersaving tip for unfortunate Optimus owners

Hello all,

If you're also an unfortunate owner of an Optimus laptop thus being unable to use the nvidia GPU, at least there's a good news/tip to know.

Currently the GPU cannot be used at all from Linux since the driver won't load, however the "idle" NVidia GPU is still sucking precious battery power.

Thanks to Michal Kottman, we have a new ACPI kernel module that allows to power off completely the (useless) GPU : http://github.com/mkottman/acpi_call

After building and installing the kernel module (afaik 2.6.34 or superior is required), you just need to run :
modprobe acpi_call
echo '\_SB.PCI0.PEG1.GFX0.DOFF' > /proc/acpi/call

According to powertop, this saves ~3W on my U30JC laptop! (which means the battery lasts around one hour longer, for free, woot! )

Of course putting this into /etc/rc.local or equivalent will enable the nice powersaving on every boot.


Hope this helps!
(until we can get proper driver support at least... there's always hope )
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