Re: [PATCH v2] thinkad_acpi: Support the battery wear control

[Julian Andres Klode]

On Tue, Dec 05, 2017 at 03:22:28PM +0100, Christoph Böhmwalder wrote:
> On Sun, Dec 03, 2017 at 11:56:40PM +0100, Ognjen Galic wrote:
> > Add support for the ACPI batteries on newer thinkpad models
> > (>Sandy Bridge) that support the setting of start and stop
> > thresholds.
> > 
> > The actual interface to the driver is a extension for the
> > existing ACPI battery driver. This was done so that users
> > can write transparently to the interface of the ACPI battery
> > driver and dont have to use some private interface
> > (for ex. /sys/devices/platform/thinkpad_acpi/).
> > 
> > Two new interfaces are created:
> > 
> > /sys/class/power_supply/BAT{0,1}/charge_start_threshold
> > /sys/class/power_supply/BAT{0,1}/charge_stop_threshold
> 
> Just tried this on my X1 Carbon (i7-3667U Ivy Lake):
> 
> # cat /sys/class/power_supply/BAT0/charge_stop_threshold
> 100
> # cat /sys/class/power_supply/BAT0/charge_start_threshold
> 100
> 
> That doesn't seem to make any sense.  Is my battery somehow reporting
> false values here?  Any way to cross check these values?

It means that both values are 0 (default). The first one is wrongly
mapped to 100, but should probably be reported as 0.

Also, the values are not mangled correctly when writing: 100
as a stop threshold should be written as 0, and and 100 as a
start threshold should be illegal, giving you:

	start = [0, 99]
	stop = [1, 100]

Which is what my patch series a few years ago implemented. I
never got to integrate that with the acpi battery driver, though.
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