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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 5 Dec 2017 23:23:43 +0100
From:   Julian Andres Klode <jak@...-linux.org>
To:     Ognjen Galic <smclt30p@...il.com>,
        Jonathan Corbet <corbet@....net>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Henrique de Moraes Holschuh <ibm-acpi@....eng.br>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-acpi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        ibm-acpi-devel@...ts.sourceforge.net
Subject: Re: [PATCH v2] thinkad_acpi: Support the battery wear control

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.
-- 
debian developer - deb.li/jak | jak-linux.org - free software dev
ubuntu core developer                              i speak de, en