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From: Henrik Rydberg <rydberg@euromail.se>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Ping Cheng <pingc@wacom.com>,
	Chris Bagwell <chris@cnpbagwell.com>,
	linux-input@vger.kernel.org
Subject: Re: [PATCH 1/3] input: wacom: Add fuzz and scale features
Date: Thu, 02 Sep 2010 22:58:36 +0200	[thread overview]
Message-ID: <4C800FFC.70303@euromail.se> (raw)
In-Reply-To: <20100902202655.GB22482@core.coreip.homeip.net>

On 09/02/2010 10:26 PM, Dmitry Torokhov wrote:

> Hi Henrik,
> 
> On Thu, Sep 02, 2010 at 08:18:35PM +0200, Henrik Rydberg wrote:
>> The signal-to-noise ratio varies between devices, but currently all
>> devices are treated the same way. In addition, some devices report
>> very low resolution, which makes the fuzz algorithm ineffective.
>> Add fuzz and scale parameters to the feature struct, allowing for
>> tailored treatment of devices.
>>
> 
> While we may adjust fuzz depending on the resolution scaling of the
> data is not kernel's task and should be left to userspace.


The scaling introduced here is for round-off errors in the EWMA filter. Maybe
the Bamboo Touch is a one-in-a-million case, but any device reporting a
resolution lower than the screen will exhibit very jerky motion without such a
scaling. I put the scaling among the features in an attempt to reduce special
code across the driver.

Henrik

  reply	other threads:[~2010-09-02 20:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-02 18:18 [PATCH 0/3] input: wacom: Initial support for Bamboo Henrik Rydberg
2010-09-02 18:18 ` [PATCH 1/3] input: wacom: Add fuzz and scale features Henrik Rydberg
2010-09-02 20:26   ` Dmitry Torokhov
2010-09-02 20:58     ` Henrik Rydberg [this message]
2010-09-02 18:18 ` [PATCH 2/3] input: wacom: Parse the Bamboo device family Henrik Rydberg
2010-09-02 21:08   ` Ping Cheng
2010-09-02 18:18 ` [PATCH 3/3] input: wacom: Add support for the Bamboo Touch trackpad (rev2) Henrik Rydberg
2010-09-02 21:02   ` Ping Cheng
2010-09-02 21:08     ` Henrik Rydberg

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