[ltp] Re: [PATCH v2] Re: Battery class driver.
Greg KH
linux-thinkpad@linux-thinkpad.org
Wed, 1 Nov 2006 11:30:14 -0800
On Wed, Nov 01, 2006 at 01:26:17PM +0000, Richard Hughes wrote:
> On Tue, 2006-10-31 at 16:06 +0200, Shem Multinymous wrote:
> >
> > In the case at hand we have mWh and mAh, which measure different
> > physical quantities. You can't convert between them unless you have
> > intimate knowledge of the battery's chemistry and condition, which we
> > don't.
>
> I'm thinking specifically for ACPI at the moment.
>
> When ACPI can't work out a value, i.e. it's not known, it returns a
> value of 0xFFFFFFFF. This can happen either for a split second on
> disconnect, or if the hardware really doesn't know the value.
>
> With the battery class driver, how would that be conveyed? Would the
> sysfs file be deleted in this case, or would the value of the sysfs key
> be something like "<invalid>".
No, the sysfs file should just not be present.
thanks,
greg k-h