On Thu, Feb 13, 2025 at 05:51:38PM +0100, Anthony Ruhier via B4 Relay wrote: > From: Anthony Ruhier <aruhier@xxxxxxxxxxx> > > The value for the POWER_NOW property is by default negative when the > battery is discharging, positive when charging. > > However on x1e laptops it breaks several userland tools that give a > prediction of the battery run time (such as the acpi command, powertop > or the waybar battery module), as these tools do not expect a negative > value for /sys/class/power_supply/qcom-battmgr-bat/power_now. They > estimate the battery run time by dividing the value of energy_full by > power_now. The battery percentage is calculated by dividing energy_full > by energy_now, therefore it is not impacted. > > While having a negative number during discharge makes sense, it is not > standard with how other battery drivers expose it. Instead, it seems > standard to have a positive value for power_now, and rely on the status > file instead to know if the battery is charging or discharging. It is > what other x86 laptops do. Documentation/ABI does not define ABI for the power_now. However for current_now it clearly defines that it can be positive or negative. > > Without the patch: > $ acpi > Battery 0: Discharging, 98%, discharging at zero rate - will never fully discharge. > > With the patch: > $ acpi > Battery 0: Discharging, 97%, 10:18:27 remaining > > --- > Signed-off-by: Anthony Ruhier <aruhier@xxxxxxxxxxx> > --- > drivers/power/supply/qcom_battmgr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) -- With best wishes Dmitry
