I just wanted to share these power saving tweaks as I've been testing out various combinations to lower power to get longer battery and more quiet fan. I got the info from here: http://www.phoronix.com/scan.php?pag...15_power&num=1
The problem was I was seeing a idling power consumption of around 10-14W on my 1830TZ which was much higher than when I first got Ubuntu on it. I remember seeing battery times of around 8 hours on idling and I wanted it back! Before these tweaks I had abt 4 hours. I know it can be tweaked even more but I'm no fanatic, just want a reasonable time and not waste power on unnecessary things but without lowering the usability.
Background is there was a power regression in the Linux kernel starting some time ago, read more on the link I gave if you're interested. This affects also Ubuntu 11.10. The biggest problem is PCI Express Active-State Power Management (PCI-E ASPM) that can again be activated, it's probably not active in your kernel. The reason it was removed by default was some hardware incompatibility so these tweaks may or may not work on your laptop. I don't know what different hardware spec the 1830 comes with but I'll share mine and if yours are the same you should see the same gain as I have seen. If yours is not the same it might still work or you should try any combination of the kernel parameters.
So, here we go. My hardware first:
If you want to read more about the options before you try just click the link to Phoronix above.
Product Name: Aspire 1830T
Wake-up Type: Power Switch
SKU Number: Calpella_CRB
Release Date: 06/04/2010
ROM Size: 2048 kB
PCI is supported
BIOS is upgradeable
BIOS shadowing is allowed
Boot from CD is supported
Selectable boot is supported
EDD is supported
Japanese floppy for NEC 9800 1.2 MB is supported (int 13h)
Japanese floppy for Toshiba 1.2 MB is supported (int 13h)
5.25"/360 KB floppy services are supported (int 13h)
5.25"/1.2 MB floppy services are supported (int 13h)
3.5"/720 KB floppy services are supported (int 13h)
3.5"/2.88 MB floppy services are supported (int 13h)
8042 keyboard services are supported (int 9h)
CGA/mono video services are supported (int 10h)
ACPI is supported
USB legacy is supported
BIOS boot specification is supported
Targeted content distribution is supported
BIOS Revision: 11.240
Socket Designation: CPU
Type: Central Processor
Family: <OUT OF SPEC>
Manufacturer: Intel(R) Corporation
ID: 55 06 02 00 FF FB EB BF
Version: Intel(R) Pentium(R) CPU U5400 @ 1.20GHz
Voltage: 0.0 V
External Clock: 1066 MHz
Max Speed: 1200 MHz
Current Speed: 1193 MHz
Status: Populated, Enabled
Upgrade: ZIF Socket
L1 Cache Handle: 0x0031
L2 Cache Handle: 0x0030
L3 Cache Handle: 0x002E
Serial Number: Not Specified
Asset Tag: FFFF
Part Number: Not Specified
Core Count: 2
Core Enabled: 2
Thread Count: 2
To test these changes out press 'e' when you see grub. move to the line (kernel boot) that ends with 'silent splash' and add:
These are the options that works best with my setup. I know a lot of 1830 comes with iX processors. If you have one of these you could also try adding:
pcie_aspm=force i915.lvds_downclock=1 i915.i915_enable_rc6=1
I did not have any luck with this option, it worked but froze my screen after a while. I believe if you have an iX proccessor you will have better luck with this option but I have not tested it since I don't have that processor.
If the computer seems unstable after adding any or all of these options you can just reboot and everything will be back to normal. If you have freezes like I had you can try pressing ctrl+alt+F1, login at the prompt and do either 'skill -KILL -u username' or just 'reboot' or 'sudo reboot'. If it seems unstable you can try adding just one or any combination of the boot options.
If you decide that you want to make the changes permanent you can edit /etc/default/grub and edit the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash". Add the options that works for you, save and then run 'sudo update-grub'.
My result, idling is with WiFi enabled and connected and Firefox started with 5 tabs open but not touching anything:
Idling before tweak: 12-14W
Idling after tweak: ~7W
Idling without Firefox and wifi:
The results are pretty amazing, it's up to 50% power save. And it runs much cooler and is finally quiet again. If you have any other tweaks or suggestions I'm all ears.
EDIT: I forgot to say that I have also ran PowerTop before measuring my power consumption, and enabled all the tunables, it does quite a difference as well.