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, 14 Mar 2007 17:43:18 +0100 Message-ID: <45F82626.8000108@gmail.com> References: <2460126662758025813@fi.muni.cz> <45EEEAA3.50009@gmail.com> <4af2d03a0703130919nb4893b1ja9ec795dcf4bf53c@mail.gmail.com> <38b3b7c0703131450v2646e63fj2be4b9dda7f928c0@mail.gmail.com> <45F722CE.9000602@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: Jiri Slaby , johann deneux , Linux kernel mailing list , linux-input@atrey.karlin.mff.cuni.cz, Anssi Hannula List-Id: linux-input@vger.kernel.org Dmitry Torokhov napsal(a): > On 3/13/07, Jiri Slaby wrote: >> Why did you remove all Cced people? Anyway I filtered some of them out >> >> johann deneux napsal(a): >> > You are right, the direction in ff_effect is meant to be an angle. >> > A dirty solution would be to use the 16 bits as two 8-bits angles. Or >> >> That would be a problem as I need 3x 16bits. >> >> > maybe we should change the API. I don't think there are many >> > applications using force feedback yet, so maybe that should be ok? >> > >> > If we change the API, we should remove the assumption that a device has >> > at most two axes to render effects. We could for instance have a >> > magnitude argument for each axis which is capable of rendering effects. >> > That might be necessary even for more common gaming devices like racing >> > wheels: One can think pedals could also be capable of force feedback >> > some day, not just the steering wheel. >> >> I can do that, but in that case, I need to know how people (especially >> those >> input one) want me to do... >> > > Since we have no idea how many programs (if any) are using force > feedback interface I would be wary of changing existing effcets and I definitely agree. > rather add new set of 3D effects. I was thinking about having "raw" (e.g. FF_RAW) effect, which would be only X "axes"/entries of u32, where X is about 10 for future use and simply posting these values further to HW (maybe after clamping or driver specific processing) from this array. This seems to be augmentation of FF_CONSTANT but the fact, it doesn't compute forces from direction. Also yet another one such as FF_VECTOR or FF_3D could be considered as one posibility, but it's still the same -- to have no more than 3 entries to pass forces... > Do we have any idea if there any users of FF out there? At least me :). I'm using it for wheel and joystick in modules for locally developped multiplatform virtual reality system. 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