You cannot update the BIOS settings while booted to the OS. You will have to reboot and hit F2 on the splash screen to access the BIOS menu.
You can configure charging settings (such as max/min charge levels) using TLP instead of the BIOS settings if you would prefer to be able to manipulate your configuration from the OS. TLP is a package available from the normal apt repositories so you can just install it from Ubuntu.
It’s NOT the BIOS menu that can be read and in certain cases written to from userland, it’s the embedded controller. Not quite the same thing. As I understand it the BIOS writes certain values to the embedded controller once on boot, then the EC handles the majority of things from there. @DHowett could probably explain it more eloquently and elegantly than that though…
I have set the charging level to 80 percent in the BIOS but I’m not sure if I understand it correctly what happens when the laptop reaches 80%. Will it stop to charge completely and only use the charger? Or will it still use the battery power but charge it like every time it drops to 79 percent ?
I have noticed that the charging LED blinks when the charging state reaches 80 percent. Does this mean the laptop doesn’t charge any more and only runs with the charger power without the battery being used?
The battery reads 81% for one reason only: No (sane) laptop will ever fully discharge to zero when it reads 0%. By default, there is a 4% reservoir on windows, and it adjusts behind-the-scenes. 100% is 100%, but 0% is 4% (saves your battery).
Here’s a graph that explains it (X-axis is actual charge, y-axis is displayed)
It’s not exactly an issue of signing… it’s just that fw-ectooltoday requires access to the processor’s raw port I/O facilities. By default, modern versions of the kernel lock down access to those instructions unless you’re (1) privileged and call iopl(3) and (2) not running in lockdown mode. Lockdown is enabled by default when Secure Boot is.
Once this patch series merges, fw-ectool can stop using port I/O and start using /dev/cros_ec. The responsibility for handling IO moves into the kernel, which is of course not subject to userspace lockdown restrictions. It’s ready for that day (and after a recent merge-up with my other MEC development branch, it will prefer /dev/cros_ec.)
Your battery does not like being force fed to 100% all the time. It’s like a whole 24" pizza with all the toppings is 100% of a battery charge.
Well imagine how uncomfortable you feel with two slices to go…that’s what a battery feels like from 80% onwards. So you then stuff the last two slices in…but you then can’t digest till several hours or even days later…
The 4% figure is due to the default power profile settings on windows, in advanced settings
The reason you get the battery displayed that way is because it’s the OS’s job to do such things. It automatically hides the processing in the background, so it both can save the battery from catching fire (and prevent the laptop from being used), and shut down safely.