Battery performance and power management

Asked by cmc302a on 2008-01-23


I migrated my laptop from Windows XP system to Ubuntu Gutsy (did not keep the Windows OS). I noticed a dramatic decrease in battery life (from ca. 2,5 hrs to less than 1), now that I've become used to Ubuntu. I have adjusted all power management settings in an effort to improve this. However, there are still some settings that Ubuntu's APM does NOT allow me to change (by the way, Ubuntu overrides the BIOS's APM settings, so there's no way of not using Ubuntu's APM, if you want APM...):

1.) My processor supports frequency-stepping, but Ubuntu says it doesn't (powernowd service won't initiate)
2.) The Toshiba APM application for Win XP used to let you customize various modes of power-schemes (up to 4 or more?). Ubuntu only allows 2: running on AC and running on battery.
3.) Also, the Toshiba utility would change the scheme automatically, depending on how much charge remained on the battery (at 100%, 75%, 50% and 25% charge steps). Ubuntu only does this when it detects that the AC has been plugged in or disconnected
4.) The "blank screen" option of the screen saver does NOT turn the screen OFF, it justs displays a black screen, but backlighting is still on, and the screen is still on. There is no "turn off screen after X minutes" option

These are my notebook's specs:

Toshiba Satellite A15-SP129
Mobile Intel Celeron 2,4 Ghz (supports stepping)
768 mb RAM (available 740.8 mb)
Ubuntu Gutsy
kernel 2.6.22-14-generic

Is there a way to fine-tune these functionality?


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In general power management on Linux lags behind Windows simply because the laptop manufacturers do not provide consistent interfaces to their hardware, and don't provide technical information about the interfaces to their hardware. This means Linux has to catch up when new laptops come out.

1) Check for a BIOS update from Toshiba. I have a Toshiba laptop which had issues such as this, and it was fixed with a BIOS update.
2) Do you really need lots of power profiles? What are you trying to achieve other than duplicate the same apps you had on Windows, on Ubuntu?
4) The "blank screen" option in gnome power manager will turn the screen off properly - you can get to this from "power management" I believe in the screensaver config.

You might also want to take a look at the application "powertop" and the website (which redirects to the gramattically incorrect

Kangarooo Jānis (kangarooo) said : #2

I also have same Problem on Dell D610 couse its video card settings are changable and on battery it takes less video. So since on Ubuntu i cant jet change video Performance its draining video on Max (witch for now isnt quite as fast also BTW).
AND battery on Ubuntu starts by showing 79% and not from 100%.

Can you help with this problem?

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