Hi Ferenc,
This patch should be better -- no integer overflow.

Regards,
Alex.

Alexey Starikovskiy wrote:
> Hi Ferenc,
>
> Good catch.
> ACPI battery interface report its state either in mW or in mA, and
> discharge rate
> in your case is reported in mW. power_supply interface does not have
> such a parameter,
> so current_now parameter is used for all cases. But in case of mW,
> reported discharge should
> be converted into mA.
>
> Please test the attached patch.
>
> Thanks,
> Alex.
>
> On Fri, Nov 21, 2008 at 3:33 AM, Ferenc Wagner <wferi@niif.hu> wrote:
>   
>> Hi,
>>
>> on my ThinkPad R50e the current_now reading seems something like 10
>> times the actual value.  Documentation/power/power_supply_class.txt
>> says it's in uA, and a tipical discharge value is around 15259000,
>> that is, 15 A on my system.  At the same time voltage is 11756000,
>> that is, 12 V, which sounds reasonable, but then the power is 15*12 VA,
>> ie 180 W, which is insane.  However, the numerical derivative of
>> energy_now gives 18 W, which is both reasonable and consistent with
>> the assumed factor of 10 error in current_now.  Is this possibly a bug
>> in 2.6.26.6?  During a quick glance over battery.c nothing obvious
>> jumped at me, but I'm no expert on this.
>> --
>> Thanks,
>> Feri.
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>>