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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Ping Cheng <pinglinux@gmail.com>
Cc: "linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
	Ping Cheng <pingc@wacom.com>,
	Peter Hutterer <peter.hutterer@who-t.net>
Subject: Re: [PATCH 2/2 v2] input: wacom_w8001 - cleanup 2FG touch code
Date: Sat, 16 Jul 2016 14:58:29 -0700	[thread overview]
Message-ID: <7724C52C-780C-4B7C-81BF-9A1EC8E78B71@gmail.com> (raw)
In-Reply-To: <CAF8JNh+fDOktK39uaXa8Fdq7v058RrwMd7rmKv8b2V_sXCXRLA@mail.gmail.com>

On July 16, 2016 2:32:27 PM PDT, Ping Cheng <pinglinux@gmail.com> wrote:
>On Fri, Jul 15, 2016 at 10:33 PM, Dmitry Torokhov
><dmitry.torokhov@gmail.com> wrote:
>> On Fri, Jul 15, 2016 at 06:19:41PM -0700, Ping Cheng wrote:
>>> On Friday, July 15, 2016, Dmitry Torokhov
><dmitry.torokhov@gmail.com> wrote:
>>>
>>> > On Fri, Jul 15, 2016 at 04:26:25PM -0700, Ping Cheng wrote:
>>> > > input_mt_sync_frame is used by other wacom devices in
>wacom_wac.c
>>> > > to close the frame and emulate pointer events. Let's follow
>them.
>>> > >
>>> > > Touch events aren't multiplexed over the same device anymore,
>the
>>> > > use of ABS_MT_TOOL_TYPE is superfluous.
>>> >
>>> > All of our touchscreen report the finger tool events, even if it
>is the
>>> > only "tool" that is being used. Does it cause problems?
>>> >
>>>
>>> No, it does not cause problem, with/without ABS_MT_TOOL_TYPE being
>set.
>>> Testing result shows all touch data are reported whether we
>explicitly set
>>> ABS_MT_TOOL_TYPE upfront or not. Plus, ABS_MT_TOOL_TYPE is not set
>in
>>> wacom.ko. We'd like to be in sync with wacom.ko.
>>>
>>> The following comments for input_mt_report_slot_state in input-mt.c
>>> explains the reason:
>>>
>>> "* Reports a contact via ABS_MT_TRACKING_ID, and optionally
>>>  * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
>>>  * inactive, or if the tool type is changed, a new tracking id is
>>>  * assigned to the slot. The tool type is only reported if the
>>>  * corresponding absbit field is set."
>>>
>>> MT_TOOL_TYPE is necessary if we report both pen and touch on the
>same
>>> interface. That is not true for this series of devices any more..
>>>
>>>
>>> > >
>>> > > Signed-off-by: Ping Cheng <pingc@wacom.com>
>>> > > Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
>>> > > ---
>>> > > v2: moved input_abs_set_res into a separate patch, as suggested
>by
>>> > > Dmitry.
>>> > > ---
>>> > >  drivers/input/touchscreen/wacom_w8001.c | 15 ++-------------
>>> > >  1 file changed, 2 insertions(+), 13 deletions(-)
>>> > >
>>> > > diff --git a/drivers/input/touchscreen/wacom_w8001.c
>>> > b/drivers/input/touchscreen/wacom_w8001.c
>>> > > index 7e807af..541a8df 100644
>>> > > --- a/drivers/input/touchscreen/wacom_w8001.c
>>> > > +++ b/drivers/input/touchscreen/wacom_w8001.c
>>> > > @@ -170,16 +170,8 @@ static void parse_multi_touch(struct w8001
>*w8001)
>>> > >               }
>>> > >       }
>>> > >
>>> > > -     /* emulate single touch events when stylus is out of
>proximity.
>>> > > -      * This is to make single touch backward support
>consistent
>>> > > -      * across all Wacom single touch devices.
>>> > > -      */
>>> > > -     if (w8001->type != BTN_TOOL_PEN &&
>>> > > -                         w8001->type != BTN_TOOL_RUBBER) {
>>> > > -             w8001->type = count == 1 ? BTN_TOOL_FINGER :
>KEY_RESERVED;
>>> > > -             input_mt_report_pointer_emulation(dev, true);
>>> > > -     }
>>> > > -
>>> > > +     w8001->type = KEY_RESERVED;
>>> > > +     input_mt_sync_frame(dev);
>>> > >       input_sync(dev);
>>> > >  }
>>> > >
>>> > > @@ -508,7 +500,6 @@ static int w8001_setup_touch(struct w8001
>*w8001,
>>> > char *basename,
>>> > >       case 5:
>>> > >               w8001->pktlen = W8001_PKTLEN_TOUCH2FG;
>>> > >
>>> > > -             __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
>>> >
>>> > Who is setting this bit then?
>>> >
>>>
>>> All MT related bits are set by input_mt_init_slots in input-mt.c,
>including
>>> BTN_TOOL_DOUBLETAP, if necessary.
>>
>> Doesn't this only happen if you call input_mt_init_slots with
>> INPUT_MT_POINTER flag?
>
>You are right. And that is what we want this driver to do - to be in
>sync with wacom.ko and rely on input-mt for common actions.

But unless I missed some other patch from you this driver passes 0 as flags to input_mt_init_slots() and by removing the double-tap bit we are breaking the driver.


Thanks.

-- 
Dmitry

  reply	other threads:[~2016-07-16 21:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-15 23:26 [PATCH 2/2 v2] input: wacom_w8001 - cleanup 2FG touch code Ping Cheng
2016-07-15 23:51 ` Dmitry Torokhov
     [not found]   ` <CAF8JNhJ4wRnH+f2beOuip=M1cUums7nB-uu6NWTcN91EVTCs+Q@mail.gmail.com>
2016-07-16  1:56     ` Fwd: " Ping Cheng
2016-07-16  5:33     ` Dmitry Torokhov
2016-07-16 21:32       ` Ping Cheng
2016-07-16 21:58         ` Dmitry Torokhov [this message]
2016-07-16 22:33           ` Ping Cheng
2016-07-19 18:37             ` Dmitry Torokhov
2016-07-19 20:07               ` Ping Cheng

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