From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Giulio Benetti <giulio.benetti@benettiengineering.com>
Cc: "Peter Hutterer" <peter.hutterer@who-t.net>,
"Rob Herring" <robh@kernel.org>,
"Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
"Henrik Rydberg" <rydberg@bitmath.org>,
linux-input@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 3/3] Input: add driver for the Hycon HY46XX touchpanel series
Date: Wed, 14 Apr 2021 10:26:13 -0700 [thread overview]
Message-ID: <YHcltT7HkJoXrX0f@google.com> (raw)
In-Reply-To: <080a71d9-d629-5589-c943-4e65a7f414d8@benettiengineering.com>
Hi Giulio, Peter,
On Wed, Apr 14, 2021 at 01:22:55PM +0200, Giulio Benetti wrote:
> Hi Peter, Dmitry,
>
> On 4/14/21 8:46 AM, Peter Hutterer wrote:
> > On Tue, Apr 13, 2021 at 10:44:07PM -0700, Dmitry Torokhov wrote:
> > > Hi Giulio,
> > >
> > > On Tue, Apr 13, 2021 at 04:44:46PM +0200, Giulio Benetti wrote:
> > > > +
> > > > + input_mt_report_pointer_emulation(tsdata->input, true);
> > >
> > > For touchscreens it does not make much sense to report BTN_DOUBLETAP,
> > > BTN_TRIPLETAP, etc, events (they are really for touchpads), so I changed
> > > this to
> > >
> > > input_mt_report_pointer_emulation(tsdata->input, false);
> > >
> > > to only report ABS_X, ABS_Y, and BTN_TOUCH, and applied.
> >
> > Can you expand on this please, just to make sure I'm not misinterpreting
> > those codes? Those bits are just for how many fingers are down (but without
> > position), dropping those bits means you restrict the device to a pure
> > single-touch screen. Or am I missing something here?
They are indeed represent number of fingers on the surface. I think I
over-simplified this a bit by saying these events are only for
touchpads, as there is allowance for BTN_TOOL_*TAP in
Documentation/input/multi-touch-protocol.rst for MT devices that may
report more contacts than what they can distinctly track, and it is
not restricted to touchpads (but I believe in reality only used by a
couple of "semi-MT" touchpad drivers).
What I meant to say that for ST fallback of MT-capable devices we
typically provide BTN_TOOL_*TAP for devices declared as INPUT_MT_POINTER
(which is touchpads) and for INPUT_MT_DIRECT and others we only provide
ABS_X, ABS_Y, ABS_PRESSURE and BTN_TOUCH (see input_mt_sync_frame()),
and I think this driver should follow the suit.
>
> I've re-tested the driver after setting input_mt_report_pointer_emulation()
> use_count to false. It works correctly with all touch points expected. That
> use_count refers to finger count of Touchpad[1]. Also you can see that even
> with use_count=false this for loop[2] is entered by counting all the
> mt->slots and then input_event() reports all of them.
That is not quite true. The loop in question locates the oldest contact
still on the surface and MT->ST mapping uses it as the "primary" point
for ST events. It is reported in addition to sending all contacts via MT
protocol as ABS_MT_SLOT, ABS_MT_POSITION_X, ABS_MT_POSITION_Y, ...
>
> I hope I've understood correctly :-)
>
> [1]: https://elixir.bootlin.com/linux/v5.12-rc7/source/drivers/input/input-mt.c#L190
> [2]: https://elixir.bootlin.com/linux/v5.12-rc7/source/drivers/input/input-mt.c#L208
>
> > then again, MT support has been in the kernel for long enough that by now
> > everything should understand it, so there's a certain "meh" factor.
Yeah, there is that too.
Thanks.
--
Dmitry
next prev parent reply other threads:[~2021-04-14 17:26 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210305163834.70924-1-giulio.benetti@benettiengineering.com>
2021-03-05 16:38 ` [PATCH 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-03-05 19:34 ` Giulio Benetti
2021-03-06 19:28 ` Rob Herring
2021-03-06 19:41 ` Rob Herring
2021-04-01 18:37 ` Giulio Benetti
2021-04-01 22:24 ` Giulio Benetti
2021-04-01 23:03 ` [PATCH v2 0/3] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-01 23:03 ` [PATCH v2 1/3] dt-bindings: Add Hycon Technology vendor prefix Giulio Benetti
2021-04-01 23:03 ` [PATCH v2 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-02 8:36 ` Jonathan Neuschäfer
2021-04-02 15:17 ` Giulio Benetti
2021-04-01 23:03 ` [PATCH v2 3/3] Input: add driver for the Hycon HY46XX touchpanel series Giulio Benetti
2021-04-02 8:59 ` Jonathan Neuschäfer
2021-04-02 15:23 ` Giulio Benetti
2021-04-02 16:16 ` [PATCH v3 0/3] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-02 16:16 ` [PATCH v3 1/3] dt-bindings: Add Hycon Technology vendor prefix Giulio Benetti
2021-04-02 16:16 ` [PATCH v3 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-06 13:24 ` Rob Herring
2021-04-07 17:57 ` Giulio Benetti
2021-04-07 18:56 ` Rob Herring
2021-04-07 19:17 ` Giulio Benetti
2021-04-06 13:37 ` Jonathan Neuschäfer
2021-04-06 14:07 ` Giulio Benetti
2021-04-07 17:49 ` [PATCH v4 0/3] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-07 17:49 ` [PATCH v4 1/3] dt-bindings: Add Hycon Technology vendor prefix Giulio Benetti
2021-04-08 20:16 ` Rob Herring
2021-04-07 17:49 ` [PATCH v4 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-08 20:21 ` Rob Herring
2021-04-11 11:37 ` Giulio Benetti
2021-04-11 11:48 ` [PATCH v5 0/3] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-11 11:48 ` [PATCH v5 1/3] dt-bindings: Add Hycon Technology vendor prefix Giulio Benetti
2021-04-12 15:05 ` Rob Herring
2021-04-12 15:12 ` Giulio Benetti
2021-04-13 13:35 ` Rob Herring
2021-04-13 14:44 ` [PATCH v7 0/3] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-13 14:44 ` [PATCH v7 1/3] dt-bindings: Add Hycon Technology vendor prefix Giulio Benetti
2021-04-14 5:44 ` Dmitry Torokhov
2021-04-13 14:44 ` [PATCH v7 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-13 16:36 ` Rob Herring
2021-04-14 5:44 ` Dmitry Torokhov
2021-04-13 14:44 ` [PATCH v7 3/3] Input: add driver for the Hycon HY46XX touchpanel series Giulio Benetti
2021-04-14 5:44 ` Dmitry Torokhov
2021-04-14 6:46 ` Peter Hutterer
2021-04-14 11:22 ` Giulio Benetti
2021-04-14 17:26 ` Dmitry Torokhov [this message]
2021-04-15 6:16 ` Peter Hutterer
2021-04-14 11:24 ` Giulio Benetti
2021-04-11 11:48 ` [PATCH v5 2/3] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-12 13:20 ` Rob Herring
2021-04-12 14:46 ` Rob Herring
2021-04-12 14:49 ` Giulio Benetti
2021-04-12 15:23 ` [PATCH v6 0/2] Input: add Hycon HY46XX Touchscreen controller Giulio Benetti
2021-04-12 15:23 ` [PATCH v6 1/2] dt-bindings: touchscreen: Add HY46XX bindings Giulio Benetti
2021-04-13 15:07 ` Rob Herring
2021-04-13 15:27 ` Giulio Benetti
2021-04-13 17:58 ` Rob Herring
2021-04-13 18:34 ` Giulio Benetti
2021-04-12 15:24 ` [PATCH v6 2/2] Input: add driver for the Hycon HY46XX touchpanel series Giulio Benetti
2021-04-11 11:48 ` [PATCH v5 3/3] " Giulio Benetti
2021-04-07 17:49 ` [PATCH v4 " Giulio Benetti
2021-04-02 16:16 ` [PATCH v3 " Giulio Benetti
2021-03-05 16:38 ` [PATCH " Giulio Benetti
2021-03-05 19:00 ` Dmitry Torokhov
2021-03-05 19:31 ` Giulio Benetti
2021-03-05 19:54 ` Giulio Benetti
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=YHcltT7HkJoXrX0f@google.com \
--to=dmitry.torokhov@gmail.com \
--cc=devicetree@vger.kernel.org \
--cc=giulio.benetti@benettiengineering.com \
--cc=j.neuschaefer@gmx.net \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peter.hutterer@who-t.net \
--cc=robh@kernel.org \
--cc=rydberg@bitmath.org \
/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).