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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Jiri Kosina <jkosina@suse.cz>
Cc: linux-input@vger.kernel.org, vojtech@ucw.cz,
	Przemo Firszt <przemo@firszt.eu>
Subject: Re: Supporting Battery Strength from my Bluetooth Mouse
Date: Mon, 21 Nov 2011 08:38:21 -0800	[thread overview]
Message-ID: <4ECA7E7D.80207@goop.org> (raw)
In-Reply-To: <alpine.LNX.2.00.1111201110480.15187@pobox.suse.cz>

On 11/20/2011 02:26 AM, Jiri Kosina wrote:
>> Given that this is a generic HID thing, where should it go?  Should 
>> hid-core.c go around trying to create new power supplies?
> If devices which present the battery status in a standard way start to 
> appear, we definitely should make it more generic compared to the add-hoc 
> handling we currently have in Wacom and Wiimote drivers.

OK.

> This would however force us to have a separate driver on HID bus for
> such devices. I'd prefer to have this in generic code (we are handling
> gazillions of devices just by hid-core/hid-input without any need for
> additional hidbus driver) if possible. I haven't personally came
> across many devices that would present bogus Battery status in their
> report descriptor, but it'll probably require some more investigation.

I have no problem just doing it for all devices unconditionally (well,
conditional on Battery Strength) if you don't think it would be a problem.

>> Bluetooth, for example, has a separate descriptor entry about whether 
>> the device is battery powered which is much more likely to be accurate 
>> than the generic HID descriptor, and it can call the power supply helper 
>> as part of the HID setup.
>>
>> Does that sound reasonable?
> Making the battery / power_supply initialization part of low-level HID 
> transport initialization (usb/bluetooth) makes probably the most sense, 
> yes.

Though unfortunately it looks like the SDP data that contains that
information is only parsed by usermode, and so isn't available to the
kernel.  That makes a generic HID-wide approach look more appealing.

> That depends a bit on the type of the event (EV_KEY has to handle 
> auto-repeat for example, etc). See the switch in input_handle_event() 
> which contains the logic behind what is happening when 'duplicate' event 
> is coming through input core.

In this case, it will be EV_ABS/ABS_MISC which does have duplicates
suppressed.

Now I need to work out the control flow.  What's the best place to hook
in "register something if something is present in the descriptor"?

    J


  reply	other threads:[~2011-11-21 16:38 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-19  6:52 Supporting Battery Strength from my Bluetooth Mouse Jeremy Fitzhardinge
2011-11-19 11:18 ` Jiri Kosina
2011-11-19 21:34   ` Jeremy Fitzhardinge
2011-11-20 10:26     ` Jiri Kosina
2011-11-21 16:38       ` Jeremy Fitzhardinge [this message]
2011-11-21 17:36         ` Dmitry Torokhov
2011-11-21 17:49           ` Jeremy Fitzhardinge
2011-11-21 23:29         ` Jiri Kosina
2011-11-21 23:34           ` Jeremy Fitzhardinge
2011-11-22  0:03             ` Jiri Kosina
2011-11-23  8:49               ` [PATCH RFC] hid-input: add support for HID devices reporting Battery Strength Jeremy Fitzhardinge
2011-11-23 16:36                 ` Chase Douglas
2011-11-23 21:07                   ` Jeremy Fitzhardinge
2011-11-23 21:52                     ` Przemo Firszt
2011-11-28 21:33                 ` Jiri Kosina
2011-12-02  5:52                   ` Daniel Nicoletti
2011-12-02 17:44                     ` Jeremy Fitzhardinge
2011-12-02 18:29                       ` Daniel Nicoletti
2011-12-03  6:09                         ` Jeremy Fitzhardinge
2011-12-03  6:13                         ` [GIT PULL RFC] directly poll battery strength when reading power_supply Jeremy Fitzhardinge
2011-12-06  9:17                           ` Jiri Kosina
2011-12-08  1:56                             ` Jeremy Fitzhardinge
2012-05-19  4:10                               ` Daniel Nicoletti
2011-12-06  9:56                           ` Richard Hughes
2011-12-06 17:10                             ` Jeremy Fitzhardinge
2011-12-07 12:51                               ` Richard Hughes
2011-12-07 17:25                                 ` Jeremy Fitzhardinge
2011-12-07 17:29                                   ` Richard Hughes
2011-12-07 17:36                                     ` Jeremy Fitzhardinge
2011-12-07 17:41                                       ` Richard Hughes
2011-12-08  1:41                                     ` [GIT PULL] power_supply: add power supply scope Jeremy Fitzhardinge
2011-12-08 10:02                                       ` Anton Vorontsov
2011-12-08 10:05                                         ` Richard Hughes
2011-12-08 10:42                                           ` Anton Vorontsov
2011-12-08 10:41                                       ` Anton Vorontsov
2011-12-08 16:53                                         ` Jeremy Fitzhardinge
2011-12-08 23:36                                           ` Anton Vorontsov
2011-12-09  8:18                                             ` Jeremy Fitzhardinge
2011-12-09  9:59                                               ` Anton Vorontsov
2011-12-09 16:58                                                 ` Jeremy Fitzhardinge
2011-12-09 10:17                                       ` Anton Vorontsov
2011-12-09 17:49                                         ` Jeremy Fitzhardinge
2011-12-09 20:00                                           ` Daniel Nicoletti
2011-12-09 20:36                                             ` Jeremy Fitzhardinge
2011-12-02 17:58                     ` [PATCH RFC] hid-input: add support for HID devices reporting Battery Strength Jeremy Fitzhardinge

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