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From: Hans Petter Selasky <hps@selasky.org>
To: Ping Cheng <pinglinux@gmail.com>
Cc: Denis Akiyakov <d.akiyakov@gmail.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-input <linux-input@vger.kernel.org>,
	"nox@jelal.kn-bremen.de >> Juergen Lock" <nox@jelal.kn-bremen.de>
Subject: Re: Problems with Wacom Intuos PT M (CTH680) on FreeBSD
Date: Sat, 01 Nov 2014 08:40:19 +0100	[thread overview]
Message-ID: <54548E63.6060306@selasky.org> (raw)
In-Reply-To: <CAF8JNhJ8ZR5vvtcrOvv9-ySzN4aytBziEO90_Kif=Q4q7WgwmA@mail.gmail.com>

On 11/01/14 00:27, Ping Cheng wrote:
> If touch_input is NULL on FreeBSD, you need to figure out the root
> cause. Checking on touch_input itself would not fix the root cause...

Right.

The root cause is that FreeBSD launches two instances of the driver, 
running in two different userland processes, for the two different Wacom 
interfaces on a common USB device. In Linux the wacom interface drivers 
are running from the same kernel, and can share the data in question, 
but in FreeBSD's webcamd emulation, this doesn't work. Then the first 
wacom probe call would have to grab the second interface.

Technically speaking this is a FreeBSD only problem and I plan to 
deliver a patch with the webcamd software to fix this, like already 
suggested to you guys. This situation can also happen on Linux in case 
of a "BadUSB" device. That's why I think that the NULL check should be 
upstreamed.

--HPS

  reply	other threads:[~2014-11-01  7:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-18 10:56 Problems with Wacom Intuos PT M (CTH680) on FreeBSD Denis Akiyakov
2014-10-21 22:33 ` Dmitry Torokhov
2014-10-23  4:54   ` Denis Akiyakov
2014-10-23  5:54     ` Hans Petter Selasky
2014-10-31 23:27       ` Ping Cheng
2014-11-01  7:40         ` Hans Petter Selasky [this message]
2014-11-04  8:08           ` Dmitry Torokhov
2014-11-04 17:38             ` Ping Cheng
2014-11-04 18:06               ` Dmitry Torokhov
2014-11-07  1:30                 ` Ping Cheng

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