From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: Problems with Wacom Intuos PT M (CTH680) on FreeBSD Date: Tue, 4 Nov 2014 10:06:48 -0800 Message-ID: <20141104180648.GA440@dtor-ws> References: <54424770.9090600@gmail.com> <20141021223311.GG8609@dtor-ws> <544889FD.5030004@gmail.com> <54489803.9030803@selasky.org> <54548E63.6060306@selasky.org> <20141104080816.GB13100@dtor-ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-ie0-f171.google.com ([209.85.223.171]:57942 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751581AbaKDSGx (ORCPT ); Tue, 4 Nov 2014 13:06:53 -0500 Received: by mail-ie0-f171.google.com with SMTP id x19so8060149ier.16 for ; Tue, 04 Nov 2014 10:06:52 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Ping Cheng Cc: Hans Petter Selasky , Denis Akiyakov , linux-input , "nox@jelal.kn-bremen.de >> Juergen Lock" On Tue, Nov 04, 2014 at 09:38:38AM -0800, Ping Cheng wrote: > Hi Dmitry, > > On Tue, Nov 4, 2014 at 12:08 AM, Dmitry Torokhov > wrote: > > On Sat, Nov 01, 2014 at 08:40:19AM +0100, Hans Petter Selasky wrote: > >> 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. > > > > Hmm, looking at this again it seems that we just cross our fingers and > > hope that both interfaces are enumerated by the time we get event data > > from the device. I do not think this is quite safe. We probably should > > be checking the overall state of probing (i.e. whether we are done > > probing both interfaces) before processing data for the device. > > Are you going to make a patch to address the issue? Not in the nearest future, sorry. > > > Or maybe we should just forcibly try claiming secondary interface > > while probing primary instead of messing with shared data item. > > If we incorporate the above idea into a patch, we need to keep in mind > that not all tablets support touch data. So, not all tablets have two > interfaces. Right, but we do know the models that use multiple interfaces, right? -- Dmitry