Bug 35802 - Dell XPS-15 wrong power_unit (mW should be mA)?
Summary: Dell XPS-15 wrong power_unit (mW should be mA)?
Status: REJECTED INVALID
Alias: None
Product: ACPI
Classification: Unclassified
Component: Power-Battery (show other bugs)
Hardware: All Linux
: P1 low
Assignee: Lan Tianyu
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-05-25 12:15 UTC by stevie.trujillo
Modified: 2011-06-07 07:34 UTC (History)
1 user (show)

See Also:
Kernel Version: 2.6.39
Subsystem:
Regression: No
Bisected commit-id:

Attachments
acpidump (246.26 KB, text/plain)
2011-05-31 05:22 UTC, stevie.trujillo 		Details
Add an attachment (proposed patch, testcase, etc.)

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.
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