Difference between revisions of "Power management"
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== Where To Change Power Settings == | == Where To Change Power Settings == | ||
| − | One can pass a kernel command line parameter in the boot loader to activate power management features in certain kernel modules. If you are using systemd you can change some power management options in systemd config files or execute your own config file. pm-utils and upower | + | One can pass a kernel command line parameter in the boot loader to activate power management features in certain kernel modules. If you are using systemd you can change some power management options in systemd config files or execute your own config file. pm-utils and upower work together. pm-utils is responsible for changing the power management options while upower informs pm-utils about system changes. For example, if you unplug your laptop from AC power then upower will signal to pm-utils that the laptop is running on battery. This will cause pm-utils to change some power management options according to its config files. |
Have a look at the [[:Category:Power management|power management category]] to get an overview on what power management options exists in Archlinux:. | Have a look at the [[:Category:Power management|power management category]] to get an overview on what power management options exists in Archlinux:. | ||
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=== PCI-e ASPM === | === PCI-e ASPM === | ||
pcie_aspm=force | pcie_aspm=force | ||
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=== Enable RC6 Power Save Options === | === Enable RC6 Power Save Options === | ||
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* '''5''': enable rc6 and deepest rc6 | * '''5''': enable rc6 and deepest rc6 | ||
* '''7''': enable rc6, deep and deepest rc6 | * '''7''': enable rc6, deep and deepest rc6 | ||
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=== Change Usbcore Autosuspend Time === | === Change Usbcore Autosuspend Time === | ||
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# chmod +x <script file> | # chmod +x <script file> | ||
| − | ==== | + | == Troubleshooting == |
| − | + | === Connection problems with Atheros AR9485 Wireless Network Adapter === | |
| − | + | You may experience connection problems with the Atheros AR9485 Wireless Network Adapter, which is caused by incorrect power management functioning. You can notice the problem if you're experiencing random disconnections in [[Wikipedia:Instant messaging|IM]] or other software that keeps connection alive for a long time. | |
| − | + | In case you're using laptop, first you must disable battery power-over-perfomance feature: | |
| − | + | '''Settings / Power Manager / On Battery / Prefer power savings over perfomance''' | |
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| − | + | Next thing to do is switch off power management for adapter: | |
| + | You should add | ||
| + | {{bc|<nowiki>iwconfig wlan0 power off</nowiki>}} (assuming wlan0 is your AR9485 adapter) anywhere it can be executed on system init (or simply run it once, to fix the problem for current session) and that should do it. | ||
== See Also == | == See Also == | ||
[[CPU Frequency Scaling]] | [[CPU Frequency Scaling]] | ||
Revision as of 03:58, 27 December 2012
The aim of this page is to try to gather all the informations which are available on the topic of linux power management features. There are several places where one can change power management settings:
- Kernel command line parameters in the boot loader
- systemd
- Settings by pm-utils
- Upower
- Laptop Mode Tools
Power settings you set in one place could be overwritten in another place.
Contents
Power saving
See power saving.
Where To Change Power Settings
One can pass a kernel command line parameter in the boot loader to activate power management features in certain kernel modules. If you are using systemd you can change some power management options in systemd config files or execute your own config file. pm-utils and upower work together. pm-utils is responsible for changing the power management options while upower informs pm-utils about system changes. For example, if you unplug your laptop from AC power then upower will signal to pm-utils that the laptop is running on battery. This will cause pm-utils to change some power management options according to its config files.
Have a look at the power management category to get an overview on what power management options exists in Archlinux:.
Kernel Command Line Parameters
Append the lines to your kernel command line parameter to enable these options. If you change settings for kernel modules make sure they are either compiled into your initrd (insert module name in MODULES in /etc/mkinitcpio.conf) or pass an option via a modprobe config file (Kernel_modules#Using_files_in_.2Fetc.2Fmodprobe.d.2F).
PCI-e ASPM
pcie_aspm=force
Enable RC6 Power Save Options
i915_enable_rc6=#Nr
Where #Nr:
- 1: enable rc6
- 3: enable rc6 and deep rc6
- 5: enable rc6 and deepest rc6
- 7: enable rc6, deep and deepest rc6
Change Usbcore Autosuspend Time
usbcore.autosuspend=
pm-utils Settings
The pm-utils (see also: Pm-utils#Power_saving) package provides quirks for suspend to RAM and suspend to disk but also includes some scripts for power management. You need upower which registers power changes and signals that information to pm-utils.
Enable SATA Link Power Management
Execute the following command to enable SATA link power management when on battery:
# echo SATA_ALPM_ENABLE=true > /etc/pm/config.d/sata_alpm
Scripts For Pm-utils Which Enable Power Management Options
These scripts have to be made executable via
# chmod +x <script file>
Troubleshooting
Connection problems with Atheros AR9485 Wireless Network Adapter
You may experience connection problems with the Atheros AR9485 Wireless Network Adapter, which is caused by incorrect power management functioning. You can notice the problem if you're experiencing random disconnections in IM or other software that keeps connection alive for a long time. In case you're using laptop, first you must disable battery power-over-perfomance feature: Settings / Power Manager / On Battery / Prefer power savings over perfomance
Next thing to do is switch off power management for adapter: You should add
iwconfig wlan0 power off(assuming wlan0 is your AR9485 adapter) anywhere it can be executed on system init (or simply run it once, to fix the problem for current session) and that should do it.