linux-kernel - Re: [PATCH v9 1/4] gadget: Introduce the usb charger framework

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:	Wed, 06 Apr 2016 11:05:26 +0300
From:	Felipe Balbi <balbi@...nel.org>
To:	Peter Chen <hzpeterchen@...il.com>
Cc:	Baolin Wang <baolin.wang@...aro.org>, gregkh@...uxfoundation.org,
	sre@...nel.org, dbaryshkov@...il.com, dwmw2@...radead.org,
	peter.chen@...escale.com, stern@...land.harvard.edu,
	r.baldyga@...sung.com, yoshihiro.shimoda.uh@...esas.com,
	lee.jones@...aro.org, broonie@...nel.org,
	ckeepax@...nsource.wolfsonmicro.com,
	patches@...nsource.wolfsonmicro.com, linux-pm@...r.kernel.org,
	linux-usb@...r.kernel.org,
	device-mainlining@...ts.linuxfoundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 1/4] gadget: Introduce the usb charger framework

Peter Chen <hzpeterchen@...il.com> writes:
> On Wed, Apr 06, 2016 at 10:38:23AM +0300, Felipe Balbi wrote:
>> Peter Chen <hzpeterchen@...il.com> writes:
>> > On Fri, Apr 01, 2016 at 03:21:49PM +0800, Baolin Wang wrote:
>> >  +
>> >> +static struct attribute *usb_charger_attrs[] = {
>> >> +	&dev_attr_sdp_current.attr,
>> >> +	&dev_attr_dcp_current.attr,
>> >> +	&dev_attr_cdp_current.attr,
>> >> +	&dev_attr_aca_current.attr,
>> >> +	&dev_attr_charger_type.attr,
>> >> +	&dev_attr_charger_state.attr,
>> >> +	NULL
>> >> +};
>> >
>> > The user may only care about current limit, type and state, why they
>> > need to care what type's current limit, it is the usb charger
>> > framework handles, the framework judge the current according to
>> > charger type and USB state (connect/configured/suspended).
>> 
>> it might be useful if we want to know that $this charger doesn't really
>> give us as much current as it advertises.
>> 
>
> As my understanding, the current limit is dynamic value, it should
> report the value the charger supports now, eg, it connects SDP, but
> the host is suspended now, then the value should be 2mA.

yes, and that's the limit. Now consider we connect to DCP or CDP and
limit is 2000mA but we're charging at 1000mA ;-)

-- 
balbi

Download attachment "signature.asc" of type "application/pgp-signature" (819 bytes)