Bug 35802

Summary:	Dell XPS-15 wrong power_unit (mW should be mA)?
Product:	ACPI	Reporter:	stevie.trujillo
Component:	Power-Battery	Assignee:	Lan Tianyu (tianyu.lan)
Status:	REJECTED INVALID
Severity:	low	CC:	lenb
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.39	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	acpidump

Description stevie.trujillo 2011-05-25 12:15:07 UTC

The computer is supposed to have a "Primary 6-cell 56W/HR LI-ION".

$ cat /proc/acpi/battery/BAT0/state 
present:                 yes
capacity state:          ok
charging state:          discharging
present rate:            1179 mW
remaining capacity:      3907 mWh
present voltage:         11615 mV

When full, capacity is just over 5000mWh. Present rate is ~3500mW when using 400% cpu (Intel(R) Core(TM) i5-2540M CPU @ 2.60GHz). I think these numbers are way too low, making me believe the unit is supposed to be mA instead of mW.

m=1/1000 right?

Comment 1 Len Brown 2011-05-31 01:08:05 UTC

please attach the output from acpidump

Comment 2 stevie.trujillo 2011-05-31 05:22:52 UTC

Created attachment 60182 [details]
acpidump

Comment 3 Lan Tianyu 2011-06-07 07:34:23 UTC

The Power Unit flag in the DSDT is fixed to be zero which means the "mW" unite. 

> I think these numbers are way too low, making me believe the unit is 
> supposed to be mA instead of mW.

Just like you said, the values of "present rate" and "remaining capacity" in the "mW" unite are too low. Those values is returned from the method "_BST" of DSDT. The unite maybe mA.

This is not a bug of linux kernel. It is caused by the BIOS.