linux-kernel - RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life charging mode

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]

Message-ID: <23e76b5eda0849fdb4e1ef8b81807558@KULX13MDC113.APAC.DELL.COM>
Date:   Wed, 24 Jun 2020 03:51:38 +0000
From:   <Crag.Wang@...l.com>
To:     <Mario.Limonciello@...l.com>, <crag0715@...il.com>,
        <sre@...nel.org>
CC:     <mathewk@...omium.org>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life
 charging mode

> > > Since this is normally only done in the factory context, can you
> > > please confirm does something need to be artificially done to block
> > > userland from trying to set the battery charging to this mode?  Or
> > > will the EC already
> > handle
> > > blocking it directly?
> >
> > This is a feature of the battery, when the EC receives this setting it
> > will be sent to the battery and stored there. Afterwards any attempt
> > to change this mode will return a failure.
> 
> Sorry this still isn't clear to me.  You're saying that if EC receives longlife
> setting it will be able to do this in the field?  If so, then I think this patch will
> need to block that setting to not allow field conversions into longlife mode.
> 
EC does handle blocking the attempts from changing the mode.

EC reads current mode ahead of a new setting. If it sees permanent long life
already in use then any attempt to put the battery charging in a different mode
will get failure 0x01 from EC.

> >
> > It's even better to block mode selection in the userland if long life
> > mode already in use.
> 
> Yes, I agree.  This sounds like a good follow up to me too.