From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: Re: [RFC 1/2] Input: ff, add FF_RAW effect Date: Thu, 19 Apr 2007 17:38:05 +0200 Message-ID: <46278CDD.2000007@gmail.com> References: <210731960111436322@karneval.cz> <462688AB.4060707@gmail.com> <38b3b7c0704182125q1928c5barad21ed603088ab04@mail.gmail.com> <200704190058.11625.dtor@insightbb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200704190058.11625.dtor@insightbb.com> Sender: owner-linux-input@atrey.karlin.mff.cuni.cz List-Help: List-Owner: List-Post: List-Unsubscribe: To: Dmitry Torokhov Cc: johann deneux , linux-kernel@vger.kernel.org, stenyak@gmail.com, linux-input@atrey.karlin.mff.cuni.cz List-Id: linux-input@vger.kernel.org Dmitry Torokhov napsal(a): > I have been thinking about this and I don't think that exporting motor > data is a good idea, at least not in case of Phantom driver. The fact > that there are 3 motors is a hardware implementation detail and it > is not interesting for general application. Ok, so what about torques (despite it's still something like FF_RAW or motor descriptor)? It seems not to be so bad called effect name -- not only phantom uses torques on motors as an unit of force, for example I get this by quick googling: http://www.caip.rutgers.edu/~bouzit/lrp/glove.html They use there some motors with 14 torque values too, so the phantom isn't the only device which uses this approach. > My understanding that the end result of controlling these 3 motors Actually there is also a version with 6 motors :). > is a force vector (I don't know if there is such english term, this > is a literal translation from russian) applied to user's hand. Better say torques vector. You must compute a torque for each place from the 3d (or bigger) vector of forces in different way for each device that exists -- this means forces are not independent unit, torques are in the meaning of layer which doesn't care about what is connected above and below it. > If we are interested in using FF API we need to come up with a way > to express this effect without exposing implementation details of > one particular device. Still, torques are better named raw/motor values, which goes to the device and I'm sceptic about inventing something class-better than this. regards, -- http://www.fi.muni.cz/~xslaby/ Jiri Slaby faculty of informatics, masaryk university, brno, cz e-mail: jirislaby gmail com, gpg pubkey fingerprint: B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E