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Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation

From "H. Nikolaus Schaller" <hns@goldelico.com>
Newsgroups linux.kernel
Subject Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation
Date 2017-02-21 07:40 +0100
Message-ID <tdchc-7eH-5@gated-at.bofh.it> (permalink)
References (1 earlier) <tcZtG-7aS-63@gated-at.bofh.it> <td28a-rt-17@gated-at.bofh.it> <td3nA-1p5-9@gated-at.bofh.it> <td3GV-1vZ-13@gated-at.bofh.it> <td49X-1GG-15@gated-at.bofh.it>
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Hi,

> Am 20.02.2017 um 22:50 schrieb Dmitry Torokhov <dmitry.torokhov@gmail.com>:
> 
> On Mon, Feb 20, 2017 at 1:27 PM, H. Nikolaus Schaller <hns@goldelico.com> wrote:
>> 
>>> Am 20.02.2017 um 22:08 schrieb Pali Rohár <pali.rohar@gmail.com>:
>>> 
>>> On Monday 20 February 2017 20:42:15 Pali Rohár wrote:
>>>> Hi Nikolaus!
>>>> 
>>>> On Monday 20 February 2017 17:50:04 H. Nikolaus Schaller wrote:
>>>>> Hi Dmitry,
>>>>> 
>>>>>> Input driver may set resolution for given axis in units per mm
>>>>>> (or units per radian for rotational axis ABS_RX, ABS_RY,
>>>>>> ABS_RZ), and if you check the binding, you can use
>>>>>> "touchscreen-x-mm" and "touchscreen-y-mm" to specify the size of
>>>>>> entire touch surface and set resolution from it so that
>>>>>> userspace can calculate the proper scaling factor.
>>>>> 
>>>>> How is this information exposed by the kernel to user-space? By
>>>>> scanning the DT file or tree?
>>>> 
>>>> Set input_abs_set_res() from kernel. And in userspace call EVIOCGABS
>>>> ioctl() on input device. Look at struct input_absinfo, you should
>>>> have all needed information here. This is generic input interface,
>>>> no DT is needed.
>>> 
>>> Looking at kernel code... via EVIOCSABS ioctl() you can even set
>>> resolution from userspace for specified input device.
>>> 
>>> So this could be potentially used for calibrating input device from
>>> userspace? (In case DT data will not fully match current HW)
>>> 
>>>> I hope that XServer is already using it for evdev devices...
>>>> 
>>>> For whole implementation look at evtest program. That should be good
>>>> starting point for your userspace implementation.
>>>> 
>>>> While I'm watching this discussion... in my opinion kernel should
>>>> just invert input axes (when needed)
>> 
>> It is questionable why it should do that at all then.
> 
> Because the task of the kernel is to provide unified view of the
> hardware. Axis swapping and inversion is needed to that "up" is always
> "up" and "right" is always "right".

Hm. Why not touching pixel (0,0) on the touch is always pixel (0,0) on the
screen and touching pixel (639,479) is always (639,479)?

I think it is time to end this discussion.

It has show me how much a mess and half-baked area this is, which I did
not expect. I read contradicting messages from different people:

* don't break user space because it is carved in stone
* fix users space if you want to do it properly
* scaling by +/-1 and shifting by full range is ok
* scaling by ts-size/adc-range and shifting by adc_min is not ok
* full numeric ADC resolution is required but subpixel coordinates is not acceptable

I will monitor this to see if this becomes sorted out before submitting anything
new.

BR and thanks,
Nikolaus

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Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2017-02-17 21:50 +0100
  Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Sebastian Reichel <sre@kernel.org> - 2017-02-18 04:30 +0100
    Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-18 12:40 +0100
      Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Sebastian Reichel <sre@kernel.org> - 2017-02-19 00:50 +0100
        Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 13:10 +0100
          Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Sebastian Reichel <sre@kernel.org> - 2017-02-19 21:20 +0100
            Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 18:00 +0100
  Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Andreas Kemnade <andreas@kemnade.info> - 2017-02-18 09:20 +0100
  Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-18 10:20 +0100
    Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-18 12:40 +0100
      Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-18 19:10 +0100
        Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-18 20:30 +0100
          Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 00:00 +0100
            Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 13:10 +0100
              Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 15:20 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 18:10 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 18:20 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 19:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 20:10 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 20:40 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 22:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-19 23:10 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 23:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 18:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-20 20:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 21:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Petr Cvek <petr.cvek@tul.cz> - 2017-02-20 23:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 09:40 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Andreas Kemnade <andreas@kemnade.info> - 2017-02-19 23:40 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-19 23:50 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 18:00 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-20 20:40 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 21:30 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 22:00 +0100
  Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-18 12:40 +0100
    Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2017-02-20 02:20 +0100
      Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 18:00 +0100
        Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 20:50 +0100
          Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 21:40 +0100
            Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 22:10 +0100
              Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 22:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 23:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 07:50 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-21 10:00 +0100
          Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 22:10 +0100
            Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-20 22:30 +0100
              Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2017-02-20 23:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2017-02-20 23:30 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 08:00 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Petr Cvek <petr.cvek@tul.cz> - 2017-02-20 23:40 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 23:50 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 07:40 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-21 10:10 +0100
                Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Andreas Kemnade <andreas@kemnade.info> - 2017-02-21 18:20 +0100
              Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-20 23:10 +0100
                Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 08:00 +0100
          Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation "H. Nikolaus Schaller" <hns@goldelico.com> - 2017-02-21 08:20 +0100
            Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pali Rohár <pali.rohar@gmail.com> - 2017-02-21 09:50 +0100
              Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new  common binding names, pre-calibration, flipping and rotation Christ van Willegen <cvwillegen@gmail.com> - 2017-02-21 10:00 +0100
        Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding  names, pre-calibration, flipping and rotation Pavel Machek <pavel@ucw.cz> - 2017-02-21 12:10 +0100

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