Dell XPS 13 9380: no presets accepted

[tremby]

I get the error message Preset error: preset "max-lifespan" not compatible with Dell: hardware enforces start = stop - 5, got start=50 stop=80 whenever I try to use one of the presets.

If I understand that message correctly (it could perhaps be reworded to be easier to understand?) Dell will only let me set start to a number 5 less than whatever stop is. Is that right?

If so, wouldn't it make sense for the presets to do the best they can within the constraints? Would "max lifespan" then mean 75-80, balanced also 75-80, full charge 95-100, plugged in 75-80 again?

Otherwise the presets just aren't useful on this hardware. (I do notice that the docs call them "built-in presets", but I don't see anywhere describing how to set new ones.)

Other observations from a first-time user which seem too small to open other tickets (though I will if you'd like me to):

• It's telling me Cycles: 0 which I'm guessing means it just doesn't have that information. Better to not show it at all than show an incorrect number IMO.
• It's saying 0.7W right now, but another battery monitor I have (part of waybar) is telling me 6.69W are being drawn. Could one of these be off by a factor of 10? I wouldn't know which.
• If my hardware only supports having these two numbers exactly 5 different from each other, why when I started up batctl for the first time did it show me 50% and 90%? Was that the actual setting, or was that some default display?

[Ooooze]

All fixed, thanks for the detailed feedback:

Presets now auto-adapt to Dell's gap constraint — max-lifespan → 75/80, full-charge → 95/100, etc. Start and stop are linked in the TUI too, so adjusting one moves the other.
Cycles: 0 is now hidden when the hardware doesn't report it.
Power reading — hard to diagnose remotely. Could you check cat /sys/class/power_supply/BAT0/power_now? batctl divides that value by 1,000,000 (µW → W).
50/90 on first launch — those were the actual values from your hardware, not defaults.
Update to the latest version and presets should just work.

[tremby]

Presets now auto-adapt to Dell's gap constraint — max-lifespan → 75/80, full-charge → 95/100, etc. Start and stop are linked in the TUI too, so adjusting one moves the other.
Cycles: 0 is now hidden when the hardware doesn't report it.

Great! Confirmed all working on my end. Much better.

Power reading — hard to diagnose remotely. Could you check cat /sys/class/power_supply/BAT0/power_now? batctl divides that value by 1,000,000 (µW → W).

I have no power_now, though I do have a directory called power there with things like async, control, runtime_status in it. Next do that directory I see current_now and voltage_now, and they look to be in microamps and microvolts. If I multiply those like this

watch -n 1 'python -c "print($(cat /sys/class/power_supply/BAT0/voltage_now)e-6 * $(cat /sys/class/power_supply/BAT0/current_now)e-6)"'

...I get numbers which look very similar to what the battery monitor in waybar is telling me.

Meanwhile I'm getting numbers about a fifth to a tenth of those from batctl. I looked through other things provided in that /sys/class/power_supply/BAT0 tree and didn't figure out where those numbers might be coming from.

50/90 on first launch — those were the actual values from your hardware, not defaults.

So I'm not constrained to start and stop being 5 percentage points apart? 50 and 90 don't fit that constraint!