Is there any way to unload modules in Ubuntu (e.g., keyboard, USB, graphics etc) to save power? I don't want to use
powertop for that, but I want to manually find these modules and unload them.
You have two questions, joined at the middle... But each question has a different context.
Yes you can unload modules, possibly saving RAM. But doing so is rarely going to translate into lower power use, and sometimes power use could go up if the thing you unloaded were providing an efficiency boost. Unloading an optimized graphics module could have your system falling back on unaccellerated vides which uses more CPU power, for example.
There is also no guarantee that device without driver commanding it would be in any kind of idle mode. It's job of the driver to put the device into on/sleep/off modes depending on OS situation, and without the driver device might be in any of those three.
If you only connect to this system via ssh, then you can configure the server to not boot into X. Edit innittab in /etc, and set the default run level to 3, and your system will boot and load into the console prompt.
Best thing is use a utility to manage power for you, and set it to max power savings.
You are only going to be able to measure whole system power, either through the OS or at the outlet using a Kill-a-watt device. You may see the overall numbers change with experimentation to your configuration. I am not aware of a method to track power of just a hardware subsystem.
I don't know of any way to directly monitor power consumption from modules. As far as I know
You can list loaded modules with
On my system this returns
If I want to unload any modules that has to do with video I guess I'd unload the module video. But what about the module i915? We can learn about it by doing:
It tells me that the module i915 is for Intel graphics so it makes sense to unload that module as well if I want to unload everything that has to do with video. Also it might make sense to do
to see what modules i915 depends on. It might show other candidates for unloading.
Another way to go is to go through all loaded modules and check whether you need them or not. First do
Then you simply run
To unload a module either do