I can’t find an active thinkpad centric community on here I am just going to post here. My Thinkpad T480s, 16 GB RAM, 238 GB SSD is randomly shutting off while at like 50%. When I try to open it back up it always is dead and I have to connect charger to boot it up again. Why is this happening? Is it battery issue? It complains about not being able to read temp2_input while shutting down and sometimes say PM usage count underflow. Not sure what that is supposed to mean.
When you say you need to connect the charger to get it to boot up again, do you mean boot to Linux or even to just show the BIOS? If the former, it might be that the battery level isn't being read correctly by the OS, but if it's the latter, the battery or its related circuitry is likely failing and you'll need a replacement battery.
In that case, I don't think the problem is with Arch. The battery is likely shot, as going from partly charged -> dead that quickly is a very common symptom of one that's reached the end of its life.
Are you using battery thresholds and keeping your laptop connected? There is a bug in ThinkPads, at least with my t480, in which the batteries get discharged over time but doesn't get reported which causes the sudden power off. If you are using TLP I suggest you to either force a full charge or a recalibration to charge your battery properly.
Also don't discard the possibility of having a broken battery.
That sort of sounds like whatever is displaying battery remaining is somehow getting things wrong, assuming that the battery is actually discharged. I can't think of much that would prevent you from at least being able to power up to the BIOS if you honestly had battery charge.
You can see what the kernel is telling userspace in:
/sys/class/power_supply/BAT0/energy_full
And
/sys/class/power_supply/BAT0/energy_now
Other things that might cause it...there is some software that will auto-hibernate or similar when your battery reaches a certain threshhold. If you consistently have the thing go down at 50%, that could do it. But I don't know why that would prevent you from booting the thing without charging it. You tried holding the power button for seven seconds or so to make sure that the thing is really powered off and not in some suspend mode or something and ignoring taps on the power button?
Yeah I think that's a battery issue. If you can run the computer fine without it, that might eliminate the probability. Maybe check if a firmware update is needed, but I think simply if the battery hasn't been swapped, it's probably due for one.
I use Fedora on my T470 with no issues. It might just be Arch. Have you tried other distros? I wish there was a ThinkPad community here.
I also use Fedora on a 2008 Mac Pro with no issues. I'm really surprised how good it is because I've been using Linux since the 90s and never had it just run smoothly on my older hardware.