From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Petter Selasky Subject: Re: Problems with Wacom Intuos PT M (CTH680) on FreeBSD Date: Sat, 01 Nov 2014 08:40:19 +0100 Message-ID: <54548E63.6060306@selasky.org> References: <54424770.9090600@gmail.com> <20141021223311.GG8609@dtor-ws> <544889FD.5030004@gmail.com> <54489803.9030803@selasky.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from heidi.turbocat.net ([88.198.202.214]:38873 "EHLO mail.turbocat.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755049AbaKAHkK (ORCPT ); Sat, 1 Nov 2014 03:40:10 -0400 In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Ping Cheng Cc: Denis Akiyakov , Dmitry Torokhov , linux-input , "nox@jelal.kn-bremen.de >> Juergen Lock" 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