Messages in this thread | | | From | Neil Brown <> | Date | Tue, 1 Jul 2003 19:40:30 +1000 | Subject | Re: [RFC/PATCH] Touchpads in absolute mode (synaptics) and mousedev |
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On Tuesday July 1, dtor_core@ameritech.net wrote: > Hi, > > I was trying to teach mousedev to bind to new synaptics driver. This > may be useful for gpm and other programs that don't have native event > processing module written yet. Unfortunately absolute to relative > conversion in mousedev only suits for tablets (digitizers) and not for > touchpads because: > > - touchpads are not precise; when I take my finger off touchpad and then > touch it again somewhere else I do not expect my cursor jump anywhere, > I only expect cursor to move when I move my finger while pressing > touchpad.
Yep, that's a bug. mousedev needs to know when there is or isn't a finger and ignore absolute differences when there is no finger.
> - synaptics has Y axis reversed from what mousedev expects. > > I tried to modify mousedev to account for differences between touchpads > in absolute mode and digitizers in absolute mode but all my solutions > required ugly flags - brrr... So what if we: > > 1. Modify mousedev so if an input device announces that it generates both > relative and absolute events mousedev will discard all absolute axis > events and will rely on device supplied relative events.
Nah. I have an ALPS dualpoint which generates ABSolute events for the touchpad part and RElative events for the pointstick part. I want them both.
> 2. Add absolute->relative conversion code to touchpad drivers themselves > as drivers should know the best how to do that. If they turn out to be > similar across different touchpads then the common module could be > made. > > What you think?
I think that mousedev should be just clever enough to mostly work and no cleverer. Anything more interesting should be done in user-space.
For example, there is the idea of treating one edge of a touch pad like a scroll wheel. I don't think this should be done in the kernel. I have just started working on a program to do this. It opens /dev/input/event1 (in my case) to read events from the touchpad. It uses an ioctl to "grab" the device so mousedev doesn't see any events directly. Then it opens /dev/input/uinput and registers itself as a mouse-like device. It copies event from one to the other with some translation. It will eventually do all the magic abs->rel translations that I want and notice corner-taps and such. At the moment it only does some simple mapping of button events so that I can use one of my two 'left' buttons as a 'middle' button.
I actually think that it should be possible to do everything in user-space. I find it quite awkward that I *cannot* get a clear channel from a user-space program to the PS/2 aux port like I could in 2.4 via /dev/psaux. I would really like to be able to open some device, "GRAB" it, and then have complete control of the PS/2 AUX port. Then I could similarly open /dev/input/uinput and do exactly what translations I wanted.
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