On Wed, Sep 14, 2011 at 12:54 PM, Ping Cheng <[email protected]> wrote: > On Tue, Sep 13, 2011 at 7:26 PM, <[email protected]> wrote: >> From: Chris Bagwell <[email protected]> >> >> Tablet reports a distance of 0 right at highest point possible >> to be in proximity and distance_max when touching tablet. Inverse >> the distance since user land has no way of knowing ABS_DISTANCE >> is not distance from tablet. > > If you want to reverse this value, you'll need to update > xf86-input-wacom as well. >
Ahh, thats what the application is. I was searching for someone using ABS_DISTANCE but was ignoring xf86-input-wacom results. It looks like we are OK here after reviewing current logic. Inside xf86-input-wacom, ABS_DISTANCE is only looked at distance for the Cursor device (mouse pucks) to short circuit proximity logic and make it act more like a mouse. Since Bamboo doesn't have a mouse tool, its OK that it doesn't report distance like older Protocol 4 devices. The xf86-input-wacom logic basically shows the issue I'm trying to avoid. There is no way for kernel driver to say if ABS_DISTANCE is starting at tablet or starting at out-of-prox point. We were previously squeaking by because it was basing it off Protocol 4 vs. Protocol 5 detection. Now that we are moving towards Protocol Generic to handle all types of tablets/touchscreens, we lose that ability. So I propose this long term definitions for ABS_DISTANCE: Protocol 5 - Any tool reporting ABS_DISTANCE is in distance from tablet (same as today). Protocol 4 - Only puck reports ABS_DISTANCE today and it can stay distance from out-of-proximity. Protocol Generic (Bamboo, Waltop, etc) - Right now, I only know PEN tool that reports it. We should standardize on distance from tablet or a rough approximation of that. More on rough approximation: In example of tablets that report 0 when entering proximity and 31 when touching tablet, I'm sure based on how worn a tablet and tip of pen is, some tablets may report 36, 31, or 26 while touching. In this later case, at best we can report a distance of 5 when touching the tablet. Of course, the driver is free to calibrate itself by monitoring pen tip indication to find reference height for surface. Even current xf86-input-wacom is using a fudge to account for this on cursor device so I'm sure its fine to do simplest in kernel driver. Chris ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA Learn about the latest advances in developing for the BlackBerry® mobile platform with sessions, labs & more. See new tools and technologies. Register for BlackBerry® DevCon today! http://p.sf.net/sfu/rim-devcon-copy1 _______________________________________________ Linuxwacom-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linuxwacom-devel
