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From: Hans Verkuil <hverkuil@xs4all.nl>
To: Vandana BN <bnvandana@gmail.com>, linux-media@vger.kernel.org
Subject: Re: [PATCH v5] vivid: Add touch support
Date: Wed, 13 Nov 2019 15:52:17 +0100	[thread overview]
Message-ID: <df071b52-3840-a835-360b-92a34162e63a@xs4all.nl> (raw)
In-Reply-To: <4e30563d-de55-5b70-ca7d-e68be0ba87ce@xs4all.nl>

On 11/13/19 3:15 PM, Hans Verkuil wrote:
> Hi Vandana,
> 
> I've been doing some testing with the Synaptics rmi4 driver that supports
> the touch API. I finally got a result, but it requires a bit of work in the
> vivid driver (and v4l2-ctl) because it means that vivid should use a different
> touch format to match what this driver returns.
> 
> Some background (based on what I understood from the driver): the Synaptics
> driver is used for touchpads on laptops. The touch API itself is meant for
> diagnostics only, and not for regular use. It 'captures' 21x12 points ('pixels')
> as an image containing the capacitance measurements.
> 
> It looks as if typically not all measuring points are available, instead only a
> subset is actually returning valid values in this diagnostic module.
> 
> Which points are available is reported in 'Function 55', which my Synaptics
> touchpad does not support, so instead the touch API falls back to the default
> of 21x12. Looking at the values I receive it appears that on my laptop only
> part of the bottom set of points in the touchpad is made available (16x1).
> Alternatively, this could be just a driver bug (I really do not trust the driver,
> I doubt it sees much testing so it could very well be a regression).

Yes, it is a regression. I am now able to get a proper 'picture' out of the driver:

      0      0      0      0      0      0      0      0      1      0      0      0      0      0      0     -1      0     -1      0      0      0
      0      0      0      0      0      0      0      0      1      1      1      0      0      0      0      0      0      0      0      0      0
      0      0      0      0      0      0      0      1      3      8      9      3      0      1      0      0      0      0      0      0      0
      0      0      0      0      0      0      0      1     11    131    132     14      3      0      0      0      0      0      0      0      0
      0      0      0      0      0      0      0      3     36    190    201     65      6      0      0      0      0      1      0      0      0
      0      0      0      0      0      0      0      2     41    189    200     76      1      0      0      2      0      0      1      1      1
      0      0      0      0      0      0      0      0      7     65     76     10      2      0      0      0      0      0      0      0      0
      0      0      0      0      0      0      0      0      0      0      0      0      0      0     -1      0      0      0      0      0      0
      0      0      0      0      0      0      0      0      0      0      0      0      0     -1      0      0      0      0      0      0      0
      0      0      0      0      0      0      0      0      0      0     -1      0     -1      0     -1      0      0      0      0      0      0
      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0      0
      0      0      0      0      0      0     -1      0      0     -1      0      0      0      0      0     -1      0      0      0      0      0

This is my finger resting in the middle of the touchpad.

Regards,

	Hans

  reply	other threads:[~2019-11-13 14:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191112135421.3766-1-bnvandana@gmail.com>
2019-11-13  7:37 ` [PATCH v4] vivid: Add touch support Vandana BN
2019-11-13  7:51   ` Hans Verkuil
2019-11-13 11:20     ` [PATCH v5] " Vandana BN
2019-11-13 14:15       ` Hans Verkuil
2019-11-13 14:52         ` Hans Verkuil [this message]
2019-11-15 13:23           ` [PATCH v6] " Vandana BN
2019-11-16 10:41             ` Hans Verkuil

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