Thread: HOW-TO: Possible fix of battery drain on 11.04

i'm passing along knowledge make sure issue gets press deserves.

background: alright, reads phoronix, or tomshardware knows. ubuntu 11.04 on massive power-binge, cutting battery life 50%.

http://www.tomshardware.com/reviews/...l,2943-13.html

issue has been known time, no 1 knew cause or how fix it. our friends on @ phoronix; both issues have been addressed. issue patch submitted during 2.6.38 kernel window, attempted "fix" or atleast deal with, bugs in poorly written bios in terms of power management. patch did designed do, the, hidden, net effect linux wasn't utilizing power management hardware did support, because bios said didn't. beforehand, linux kernel atleast try enable said power management, caused problems users. patch made kernel "if says doesn't, don't bother trying."

(http://www.phoronix.com/scan.php?pag...638_aspm&num=1 phoronix article more in depth analysis. summary dumbed down convience of readers)

warning: may in segment of users who's bios' cause linux hang fix enabled. not try unless know how repair system livecd

the fix: fix work on linux distro utilizing grub2, similar fix work on grub-legacy.

1) load terminal menu.
2)

code:

cd /etc/default/

3)
gnome users:

code:

gksu gedit grub

kde users:

code:

kdesudo kate grub

others:

code:

sudo nano grub

4) find line says "grub_cmdline_linux_default=" users have 'quiet splash' following that.

5) after 'quiet splash' add words "pcie_aspm=force" without quotes

6) save file , exit text editor used, nano users ctrl-x, y save following. vi/vim/emacs, you're on own don't use them.

7) run command

code:

sudo update-grub

8 ) wait grub finish updating, reboot. , enjoy longer battery life!

able 50 minutes of battery life 1 simple fix.

michael @ phoronix has said looking 2 more power-usage regressions, 1 of lies within kernel's scheduler, there's 1 effect (unless you're using custom kernel)


to revert: assuming you're system didn't start hanging when rebooted, , want revert testing purposes. follow steps 1 - 5, instead of adding "pcie_aspm=force", remove it. save. exit. , re-run sudo update-grub , reboot.

restate, if don't know how fix system livecd, don't use fix! fix won't if have correctly coded bios, linux would've activated power management correctly, poorly written bios'. isn't limited laptops, wanting tone down power usage (servers example) can use fix.

hi, think laptop (hp dv4 117nr) may 1 of laptops affected "bug" guess call it. want try fix, , confident in ability fix if makes boot hang, i'm not positive skeptical doing it. main concern wouldn't able write on files necessary because of lack of root access. there anyway can post short post on how might go fixing if hang on bootup?

Forum The Ubuntu Forum Community Ubuntu Official Flavours Support Hardware [all variants] HOW-TO: Possible fix of battery drain on 11.04

Ubuntu