linux-kernel - Re: [PATCH 5/5] power: supply: bq27xxx: Correct supply status with current draw

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: <20170528191619.GA20159@xo-6d-61-c0.localdomain>
Date:   Sun, 28 May 2017 21:16:19 +0200
From:   Pavel Machek <pavel@....cz>
To:     Paul Kocialkowski <contact@...lk.fr>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Pali Rohár <pali.rohar@...il.com>,
        "Andrew F . Davis" <afd@...com>,
        Sebastian Reichel <sre@...nel.org>,
        Chris Lapa <chris@...a.com.au>,
        Matt Ranostay <mranostay@...il.com>
Subject: Re: [PATCH 5/5] power: supply: bq27xxx: Correct supply status with
 current draw

Hi!

> The status reported directly by the battery controller is not always
> reliable and should be corrected based on the current draw information.
> 
> This implements such a correction with a dedicated function, called
> when retrieving the supply status.
> 

> @@ -1182,6 +1196,8 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
>  		else
>  			status = POWER_SUPPLY_STATUS_DISCHARGING;
>  	} else {
> +		curr = (int)((s16)curr) * 1000;

Umm.

> @@ -1190,6 +1206,18 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
>  			status = POWER_SUPPLY_STATUS_CHARGING;
>  	}
>  
> +
> +	if (curr == 0 && status != POWER_SUPPLY_STATUS_NOT_CHARGING)
> +		status = POWER_SUPPLY_STATUS_FULL;
> +
> +	if (status == POWER_SUPPLY_STATUS_FULL) {
> +		/* Drawing or providing current when full */
> +		if (curr > 0)
> +			status = POWER_SUPPLY_STATUS_CHARGING;
> +		else if (curr < 0)
> +			status = POWER_SUPPLY_STATUS_DISCHARGING;
> +	}

Are you sure this works? On N900, we normally see small currents to/from "full" battery.

Should the test be for absolute_value(curr) < something rather than for == 0?

What hw did you test it on?
										Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html