TLP erroneously putting desktop PC in battery mode

[Jason Harvey]

TLP on my desktop PC (with no battery) is putting the system into battery mode. This results in symptoms like the disk spinning down whenever it is idle for 15 seconds, which happens constantly.

This is a new symptom with an upgrade to Oracular - I ran this same system on Jammy before and did not have this symptom.

I believe this may be due to TLP seeing a battery "power supply" device for UCSI.

tlp-stat output: https://gist.github.com/alienth/60f3b53004d7849f1906241ec1868550
tlp-stat --psup output: https://gist.github.com/alienth/55ff4f906b5fd1d3e94f1b7ae8e7e819

Filed a bug with the upstream: https://github.com/linrunner/TLP/issues/768

[Jason Harvey (jason-alioth)]

Found the cause: https://github.com/linrunner/TLP/issues/768#issuecomment-2443358201

It is due to the UCSI driver, which TLP is interpreting as a power source. Since it sees no other AC sources, it assumes the system is on battery.

This would be fixable by setting `TLP_PS_IGNORE="USB"` in the config file, but I am wondering if there is some way the logic could be adjusted to handle this correctly by default. It would be easily for someone to accidentally end up in this state, leading to performance problems plaguing them with no clear cause.

Anyone running Mate on a PC that happens to have a UCSI driver loaded will experience this by default, as Oracular's `ubuntu-mate-desktop` appears to install TLP by default.

[Jason Harvey (jason-alioth)]

Comment from TLP dev here: https://github.com/linrunner/TLP/issues/768#issuecomment-2444891199

Might not be an easy way to address this from TLP's perspective.

I wonder, should Ubuntu installs elide the installation of TLP unless the system can be definitively identified as a laptop? Looks like I got it due to `ubuntu-mate-desktop` depending upon TLP.

[Jason Harvey (jason-alioth)]

Posed a question with the `ubuntu-mate-desktop` on this matter: https://answers.launchpad.net/ubuntu/+source/ubuntu-mate-meta/+question/819242