From: Benjamin Tissoires <benjamin.tissoires@gmail.com>
To: Henrik Rydberg <rydberg@euromail.se>
Cc: Jiri Kosina <jkosina@suse.cz>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
Stephane Chatty <chatty@enac.fr>
Subject: Re: [PATCH v3 0/6] hid: Introduce device groups
Date: Thu, 3 May 2012 15:37:13 +0200 [thread overview]
Message-ID: <CAN+gG=GU8NGJ70Yx8_roeA4LCohcmym7wEspbv4d_xMqbrP5hw@mail.gmail.com> (raw)
In-Reply-To: <20120503131904.GA11741@polaris.bitmath.org>
On Thu, May 3, 2012 at 3:19 PM, Henrik Rydberg <rydberg@euromail.se> wrote:
>> > 1) Add the devices in question back to the have_special_drivers list.
>>
>> Well... The device presents valid mouse and keyboard interface that
>> should be handled by hid-generic.
>> The behavior of this particular device is the following:
>> - when 1 finger is in use, then it sends events over the mouse interface
>> - when 2 fingers are present, it sends events over the multitouch interface
>> - when you physically trigger the switch mode button, a keyboard
>> appears and it sends key events over the keyboard interface, and
>> eventually mouse events if you press the "mouse" key.... ;-)
>>
>> This crap is all inherited by the fact that Microsoft do not want to
>> handle indirect touch, and the device maker found this solution to
>> counter this.
>>
>> To sum up, adding it to the have_special_drivers driver list won't
>> work as we need part of the device to be handled by hid-generic.
>
> So was this particular device never listed in have_special_drivers?
No, and that's the way it should (not being part of have_special_driver).
>
>> > 2) Add the interface type to the group descision, which should
>> > probably be done anyway. I have a patch in the pipe that, will send it
>> > later today.
>>
>> A simpler solution consists in adding the macros HID_USB_MT_DEVICE(v,
>> p) and HID_BLUETOOTH_MT_DEVICE(v, p) as you had introduced in a
>> earlier patch (I don't know why it disappeared).
>
> No, the specific entries in the hid-multitouch device list matches any
> group, so those defines were simplified away in the second version.
disagree: a device can present several interface (because it has
several "devices") and only those presenting Contact ID can and should
be handled by hid-multitouch.
Cypress for instance presents one interface for the multitouch layer,
and one other for specific controls that are seen as a keyboard.
However, in this particular case, I'm not sure we want to show this
interface to the end user.... ;-)
>
>> The problem came out because:
>> - hid-multitouch registered the triplet BUS_USB / VID / PID.
>> - For each interface, it asks udev (or the kernel) which driver to
>> use, and whatever .group was, it was always hid-multitouch that came
>> out.
>>
>> So it's just safer to specify the group for all multitouch devices.
>
> This is still confusing. I thought the real problem was that the
> non-mt interfaces do not match hid-generic. Solution 2) should take
> care of that. What I don't understand is how those other interfaces
> came to be handled by hid-generic before this patch, unless this
> device was never listed in have_special_driver.
The think is that they do match hid-generic (they get the group
HID_GROUP_GENERIC).
However they also match hid-multitouch (as hid-multitouch does not ask
for a particular group). So, if hid-multitouch is loaded __before__
hid-generic, it will be given the device whatever the match with
hid-generic.
And again, yes it was never listed in have_special_driver.
>
> Are we talking about USB_DEVICE_ID_TOPSEED2_PERIPAD_701 here?
yep
- For consistency, I'd rather specifying the group for any devices.
This because hid-multitouch can not handle other interfaces than
multitouch one. Though the catchall is interesting in the sense that
it may help us to hide unwanted interfaces.
- For backward compatibility, we should adapt each device (currently,
I only spotted this particular one) to decide if we need to catch the
group or not.
Jiri, any thought?
Benjamin
>
> Henrik
next prev parent reply other threads:[~2012-05-03 13:37 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-23 10:07 [PATCH v3 0/6] hid: Introduce device groups Henrik Rydberg
2012-04-23 10:07 ` [PATCH v2 1/6] hid: Add device group to modalias Henrik Rydberg
2012-04-23 10:07 ` [PATCH 2/6] hid: Scan the device for group info before adding it Henrik Rydberg
2012-04-24 12:31 ` Jiri Kosina
2012-04-24 12:41 ` Henrik Rydberg
2012-04-23 10:07 ` [PATCH v2 3/6] hid: Allow bus wildcard matching Henrik Rydberg
2012-04-23 10:07 ` [PATCH v3 4/6] hid: Create a generic device group Henrik Rydberg
2012-04-23 21:26 ` Gustavo Padovan
2012-04-23 22:31 ` Henrik Rydberg
2012-04-23 10:07 ` [PATCH v3 5/6] hid-multitouch: Switch to device groups Henrik Rydberg
2012-04-30 14:58 ` Benjamin Tissoires
2012-04-30 16:42 ` Jiri Kosina
2012-04-30 18:30 ` Henrik Rydberg
2012-04-30 18:51 ` Benjamin Tissoires
2012-05-01 6:35 ` Henrik Rydberg
2012-04-23 10:07 ` [PATCH 6/6] hid: Create a common generic driver Henrik Rydberg
2012-04-23 10:51 ` [PATCH v3 0/6] hid: Introduce device groups Benjamin Tissoires
2012-04-23 15:21 ` Benjamin Tissoires
2012-04-30 8:35 ` Jiri Kosina
2012-04-30 8:44 ` Jiri Kosina
2012-04-30 11:53 ` Henrik Rydberg
2012-04-30 11:55 ` Jiri Kosina
2012-05-01 12:23 ` Jiri Kosina
2012-05-01 11:03 ` Jiri Kosina
2012-05-02 5:46 ` Henrik Rydberg
2012-05-02 8:33 ` Benjamin Tissoires
2012-05-02 8:45 ` Jiri Kosina
2012-05-02 10:55 ` Benjamin Tissoires
2012-05-03 10:06 ` Benjamin Tissoires
2012-05-03 12:23 ` Henrik Rydberg
2012-05-03 12:45 ` Benjamin Tissoires
2012-05-03 13:19 ` Henrik Rydberg
2012-05-03 13:37 ` Benjamin Tissoires [this message]
2012-05-03 13:54 ` Henrik Rydberg
2012-05-03 14:04 ` Benjamin Tissoires
2012-05-03 14:16 ` Henrik Rydberg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAN+gG=GU8NGJ70Yx8_roeA4LCohcmym7wEspbv4d_xMqbrP5hw@mail.gmail.com' \
--to=benjamin.tissoires@gmail.com \
--cc=chatty@enac.fr \
--cc=dmitry.torokhov@gmail.com \
--cc=jkosina@suse.cz \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rydberg@euromail.se \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).