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From: "Henrik Rydberg" <rydberg@euromail.se>
To: Daniel Kurtz <djkurtz@chromium.org>
Cc: Chung-yih Wang <cywang@chromium.org>,
	Alessandro Rubini <rubini@ipvvis.unipv.it>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] CHROMIUM: Input: synaptics - filter out the events with low z values
Date: Wed, 22 Feb 2012 12:04:59 +0100	[thread overview]
Message-ID: <20120222110459.GA28126@polaris.bitmath.org> (raw)
In-Reply-To: <CAGS+omCU9f=DyC442+4HOF=sGhZYXne+E2ephFiOmuj-XKciMA@mail.gmail.com>

Hi Daniel,

> > So if num_fingers == 2 and only one of a and b returns
> > finger_touched() == true, we fall back to zero fingers?
> 
> Actually, yes.   In this case, we will have 2 x's and 2 y's, but not
> know which belong to a good finger and which belong to a too light
> finger....  sigh... synaptics... sigh...

I see the problem. However, ignoring it will just move the problem
forward to another bug report, will it not?  Hysteresis is a slam dunk
here.  In addition, since the low-pressure state is bound to be
transitional (soon to be followed by a real num_fingers==1 package),
simply skipping such packages might be a better option.

> > Why not introduce hysteresis for all fingers here? There is an example
> > implementation in bcm5974.c in the same directory.
> 
> Good idea, can it be in a different, follow-up patch?

Why should it be?

Thanks,
Henrik

WARNING: multiple messages have this Message-ID (diff)
From: "Henrik Rydberg" <rydberg@euromail.se>
To: Daniel Kurtz <djkurtz@chromium.org>
Cc: Chung-yih Wang <cywang@chromium.org>,
	Alessandro Rubini <rubini@cvml.unipv.it>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] CHROMIUM: Input: synaptics - filter out the events with low z values
Date: Wed, 22 Feb 2012 12:04:59 +0100	[thread overview]
Message-ID: <20120222110459.GA28126@polaris.bitmath.org> (raw)
In-Reply-To: <CAGS+omCU9f=DyC442+4HOF=sGhZYXne+E2ephFiOmuj-XKciMA@mail.gmail.com>

Hi Daniel,

> > So if num_fingers == 2 and only one of a and b returns
> > finger_touched() == true, we fall back to zero fingers?
> 
> Actually, yes.   In this case, we will have 2 x's and 2 y's, but not
> know which belong to a good finger and which belong to a too light
> finger....  sigh... synaptics... sigh...

I see the problem. However, ignoring it will just move the problem
forward to another bug report, will it not?  Hysteresis is a slam dunk
here.  In addition, since the low-pressure state is bound to be
transitional (soon to be followed by a real num_fingers==1 package),
simply skipping such packages might be a better option.

> > Why not introduce hysteresis for all fingers here? There is an example
> > implementation in bcm5974.c in the same directory.
> 
> Good idea, can it be in a different, follow-up patch?

Why should it be?

Thanks,
Henrik

  reply	other threads:[~2012-02-22 11:05 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-22  7:41 [PATCH] CHROMIUM: Input: synaptics - filter out the events with low z values Chung-yih Wang
2012-02-22  7:41 ` Chung-yih Wang
2012-02-22  8:38 ` Henrik Rydberg
2012-02-22  8:38   ` Henrik Rydberg
2012-02-22 10:26   ` Daniel Kurtz
2012-02-22 10:26     ` Daniel Kurtz
2012-02-22 11:04     ` Henrik Rydberg [this message]
2012-02-22 11:04       ` Henrik Rydberg
2012-02-22 13:12       ` Daniel Kurtz
2012-02-22 13:12         ` Daniel Kurtz
2012-02-22 15:24         ` Henrik Rydberg
2012-02-22 15:24           ` Henrik Rydberg
2012-02-24  8:27           ` Dmitry Torokhov
2012-02-24  8:27             ` Dmitry Torokhov
2012-02-24  9:08             ` Henrik Rydberg
2012-02-24  9:08               ` Henrik Rydberg
2012-02-24  9:14               ` Dmitry Torokhov
2012-02-24  9:14                 ` Dmitry Torokhov
2012-02-24  9:16                 ` Dmitry Torokhov
2012-02-24  9:16                   ` Dmitry Torokhov
2012-02-24  9:23                   ` Henrik Rydberg
2012-02-24  9:23                     ` Henrik Rydberg
  -- strict thread matches above, loose matches on Subject: below --
2012-02-21 15:07 Chung-yih Wang
2012-02-21 15:07 ` Chung-yih Wang
2012-02-21 16:35 ` Daniel Kurtz
2012-02-21 16:35   ` Daniel Kurtz

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