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From: Stanislav Brabec <utx@penguin.cz>
To: Pavel Machek <pavel@ucw.cz>
Cc: dtor@mail.ru, linux-input@vger.kernel.org, rpurdie@rpsys.net,
	lenz@cs.wisc.edu, kernel list <linux-kernel@vger.kernel.org>,
	Dirk@Opfer-Online.de, arminlitzel@web.de,
	Cyril Hrubis <metan@ucw.cz>,
	thommycheck@gmail.com,
	linux-arm-kernel <linux-arm-kernel@lists.arm.linux.org.uk>,
	dbaryshkov@gmail.com, omegamoon@gmail.com,
	eric.miao@marvell.comCyril Hrubis <metan@ucw.cz>
Subject: Re: ads7846: clean up, fix pressure reporting
Date: Sun, 09 Aug 2009 12:21:33 +0200	[thread overview]
Message-ID: <1249813293.4334.24.camel@utx.utx.cz> (raw)
In-Reply-To: <20090807180941.GF1728@ucw.cz>

Pavel Machek wrote:
> Fix pressure reporting, and clean up debug prints.

Thanks.

I see much bigger problem with both the old driver and the new ads7846
driver (2.6.30): They are very noisy on my spitz. When you tap to one
place, keep stylus pressed and just read values, you get 20-200 pixels
long pointer motion trip each second.

According to Cyril Hrubiš, it is caused by the electrical noise that
originates in the LCD display. The driver needs to read data
synchronously with the LCD refresh. He already made the fix for collie
several years ago.

The pointer test application in the PROM diagnostic utility does not
seem to exhibit any noise.


________________________________________________________________________
Stanislav Brabec
http://www.penguin.cz/~utx/zaurus


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WARNING: multiple messages have this Message-ID (diff)
From: Stanislav Brabec <utx@penguin.cz>
To: Pavel Machek <pavel@ucw.cz>
Cc: dtor@mail.ru, linux-input@vger.kernel.org, rpurdie@rpsys.net,
	lenz@cs.wisc.edu, kernel list <linux-kernel@vger.kernel.org>,
	Dirk@Opfer-Online.de, arminlitzel@web.de,
	Cyril Hrubis <metan@ucw.cz>,
	thommycheck@gmail.com,
	linux-arm-kernel <linux-arm-kernel@lists.arm.linux.org.uk>,
	dbaryshkov@gmail.com, omegamoon@gmail.com, eric.miao@marvell.com,
	Cyril Hrubis <metan@ucw.cz>
Subject: Re: ads7846: clean up, fix pressure reporting
Date: Sun, 09 Aug 2009 12:21:33 +0200	[thread overview]
Message-ID: <1249813293.4334.24.camel@utx.utx.cz> (raw)
In-Reply-To: <20090807180941.GF1728@ucw.cz>

Pavel Machek wrote:
> Fix pressure reporting, and clean up debug prints.

Thanks.

I see much bigger problem with both the old driver and the new ads7846
driver (2.6.30): They are very noisy on my spitz. When you tap to one
place, keep stylus pressed and just read values, you get 20-200 pixels
long pointer motion trip each second.

According to Cyril Hrubiš, it is caused by the electrical noise that
originates in the LCD display. The driver needs to read data
synchronously with the LCD refresh. He already made the fix for collie
several years ago.

The pointer test application in the PROM diagnostic utility does not
seem to exhibit any noise.


________________________________________________________________________
Stanislav Brabec
http://www.penguin.cz/~utx/zaurus


  reply	other threads:[~2009-08-09 10:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-07 18:09 ads7846: clean up, fix pressure reporting Pavel Machek
2009-08-07 18:09 ` Pavel Machek
2009-08-09 10:21 ` Stanislav Brabec [this message]
2009-08-09 10:21   ` Stanislav Brabec
2009-08-10 21:10   ` Richard Purdie
2009-08-09 10:51 ` Mark Brown
2009-08-09 10:54   ` Pavel Machek

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