I am Using Ubuntu 20.04 on a notebook with tlp installed.
When I am working on slight tasks I can usually have a power drainage of about 4-7 W.
Sometimes however, the power drainage goes up to more than 20 W and stays on that level.
Randomly I noticed, that by issuing the command
lspci -vnnn | perl -lne 'print if /^\d+\:.+(\[\S+\:\S+\])/' | grep VGA
I can get back to the 4-7 W level. The command gives me the following output:
00:02.0 VGA compatible controller [0300]: Intel Corporation UHD Graphics [8086:9bc4] (rev 05) (prog-if 00 [VGA controller])
That being said I will also have to mention that I am using prime-select to use my intel graphics card.
My assumption is that for some reason at some points (happens randomly after long usage but also often after suspend or hibernation) somehow the GPU is activated. However, issuing nvidia-smi when it is draining a lot of energy tells me that it can't communicate with the driver which I suppose means, that GPU is not on.
With the lspci command somehow the system notices that it is in intel mode and changes something so it gets back to the 4-7 W Power consumption.
This confuses me a lot since lspci should just read and not change anything in the configuration.
Anyways, I can see this behavior every time since it is my current workaround to hit the lscpi command in order to get back to low power consumption and increase battery life.
Does anyone know what is going on here ?
