linux-kernel - Re: [PATCH 1/2] HID: logitech-hidpp: add battery support for HID++ 2.0 devices

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Date:	Fri, 8 Jul 2016 14:34:15 +1000
From:	Peter Hutterer <peter.hutterer@...-t.net>
To:	Bastien Nocera <hadess@...ess.net>
Cc:	Jiri Kosina <jikos@...nel.org>,
	Benjamin Tissoires <benjamin.tissoires@...hat.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	Nestor Lopez Casado <nlopezcasad@...itech.com>
Subject: Re: [PATCH 1/2] HID: logitech-hidpp: add battery support for HID++
 2.0 devices

On Fri, Jul 08, 2016 at 01:21:08AM +0200, Bastien Nocera wrote:
> On Wed, 2016-06-29 at 19:28 +1000, Peter Hutterer wrote:
> > If the 0x1000 Unified Battery Level Status feature exists, expose the
> > battery
> > level.
> > 
> > The main drawback is that while a device is plugged in its battery
> > level is 0.
> > To avoid exposing that as 0% charge we make up a number based on the
> > charging
> > status.
> 
> This will require changes in UPower, so that it doesn't try to access
> the Logitech unifying devices via user-space, and uses the data from
> the kernel. Did you already file a bug?

filed now: https://bugs.freedesktop.org/show_bug.cgi?id=96857

> Note that this would also mean losing the "lux" information, but I
> don't think that's something we're that interested in exposing.

Adding that HID++ request to the kernel would be easy enough but I don't 
see anything in the power_supply_property that would match this, do you? 
Also, I don't have such a device so testing would be tricky.

Cheers,
   Peter


> 
> For example, for a keyboard that recharges via solar panels, at night:
> 
> Device: /org/freedesktop/UPower/devices/keyboard_0003o046Do4002x0004
>   native-path:          /sys/devices/pci0000:00/0000:00:14.0/usb3/3-10/3-10:1.2/0003:046D:C52B.0003/0003:046D:4002.0004
>   vendor:               Logitech, Inc.
>   model:                K750
>   serial:               197F3F23
>   power supply:         no
>   updated:              Fri 08 Jul 2016 01:17:40 CEST (95 seconds ago)
>   has history:          yes
>   has statistics:       no
>   keyboard
>     present:             yes
>     rechargeable:        yes
>     state:               discharging
>     warning-level:       none
>     luminosity:          16 lx
>     percentage:          89%
>     icon-name:          'battery-full-symbolic'