Public bug reported:
Binary package hint: linux-image-2.6.28-11-generic
Hi,
After apgrading my Thinkpad T61 to Jaunty the idle power consumption
increased by nearly 1 watt because of the Intel WiFi adapter 4965AGN
(iwl4965). In Intrepid the adapter could be switched to power saving
mode with the following command:
k...@t61:~$ bash -c "echo 5 > /sys/bus/pci/drivers/iwlagn/*/power_level"
After this command the idle power consumption with lowest display
brightness was 12.5 watt (1400x1050 nvidia graphic). Turning wireless
lan off did not further improve power consumption.
Unfortunately, changing the power level does not work in Jaunty.
Although the above command initially changes the power level to 5 and
reduces power consumption...
k...@t61:~$ sudo cat /sys/bus/pci/drivers/iwlagn/0000\:03\:00.0/power_level
SYSTEM:auto MODE:fixed INDEX:5
... it switches back to level 0 shortly afterwards and power consumption
increases by about 1 watt:
k...@t61:~$ sudo cat /sys/bus/pci/drivers/iwlagn/0000\:03\:00.0/power_level
SYSTEM:auto MODE:fixed INDEX:0
Apparently, the kernel now controls the power saving mode and overwrites
any changes made by the user. However, I never noticed any difference in
performance between power_level 5 and 0 as I use WiFi to connect to a
1.5 Mbps ADSL which is slow anyway. It would clearly be beneficial for
this setting to have the option to choose the power level permanently.
Many thanks and best wishes
Karl Martin
ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
HibernationDevice: RESUME=UUID=2cc3544b-1512-4ea0-8ef0-e1397de5c70b
MachineType: LENOVO 88892BG
NonfreeKernelModules: nvidia
Package: linux-image-2.6.28-11-generic 2.6.28-11.42
ProcCmdLine: root=UUID=6b246c4a-3c52-4c71-acdd-b43c8934a4f4 ro splash
locale=de_DE xforcevesa vga=792 resume=/dev/sda5
ProcEnviron:
PATH=(custom, user)
LANG=de_DE.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.28-11.42-generic
SourcePackage: linux
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug
--
[Jaunty] Power saving mode for Intel iwl4965 does not work
https://bugs.launchpad.net/bugs/377484
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