From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: Re: FF layer restrictions [Was: [PATCH 1/1] Input: add sensable phantom driver] Date: Wed, 21 Mar 2007 21:04:08 +0100 Message-ID: <46018FB8.1080601@gmail.com> References: <2460126662758025813@fi.muni.cz> <45F722CE.9000602@gmail.com> <45F82626.8000108@gmail.com> <45F83930.4060401@gmail.com> <8e4ff20a0703141147n4b690ab8g4cc8138d1ecc94e1@mail.gmail.com> <8e4ff20a0703141218r3add7923n74470b5e16f58c5c@mail.gmail.com> <4601339C.6010706@gmail.com> <38b3b7c0703211202p29f7865cr34960c7ea708640e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: owner-linux-input@atrey.karlin.mff.cuni.cz List-Help: List-Owner: List-Post: List-Unsubscribe: To: Dmitry Torokhov Cc: johann deneux , =?UTF-8?B?IlNUZW55YUsgKEJydW4=?= =?UTF-8?B?byBHb256w6FsZXopIg==?= , Anssi Hannula , Linux kernel mailing list , linux-input@atrey.karlin.mff.cuni.cz List-Id: linux-input@vger.kernel.org Dmitry Torokhov napsal(a): > On 3/21/07, johann deneux wrote: >> I would suggest adding a new effect type (3d effect) and extending the >> union in struct ff_effect. >> Let me know if I'm too vague, I already suggested that solution but >> got no answer. I wonder if my mail got lost, nobody understood what I >> said, or if it's just a plain bad idea. >> > > My concern with a new 3D effect is that it will be a very "simple" > effect with only constant force apllied. That might be enough for > phantom but may not be sufficient for future devices. If we add > ability to specify a "plane" for an effect we will be able to add > envelopes on top of more complex effects and get desired combined > effcet. I didn't get this too much, because I don't understand the FF layer well so far. How is this going to work? Let's say, we have 3 torque values computed in US, and this structure: struct ff_effect { __u16 direction; struct ff_trigger trigger; struct ff_replay replay; struct ff_constant_effect { __s16 level; struct ff_envelope { __u16 attack_length; __u16 attack_level; __u16 fade_length; __u16 fade_level; }; }; }; and need to pass the three 16bits torques into s16 ioaddr[0..2]. How? > I would not worry aboput extra memory needed on I-force like > devices because they just would not support additional "planes". What > about phantom? Would it have enough memory? It's a memless device -- values written into pci space are immediately felt in FF (it's just PLX chip interface to some their proprietary chip or somewhat). > On the other hand if you guys (Anssi, Johann, Jiri...) decide that a > simple new 3d effect is the most efficient solution for now and will > be enough for a few years (till we get FF v2 API) I will merge it. I won't force any of mentioned solutions, but this seems the simplest one in my eyes. thanks for clues, -- 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