On Thu, Mar 8, 2012 at 4:14 AM, Nikolai Kondrashov <spbn...@gmail.com> wrote: > On 03/08/2012 02:18 AM, Jason Gerecke wrote: >> >> Our kernel driver reports values from [0, 127] with 0 corresponding to >> top/left and 127 to bottom/right. The midpoint is assumed to be >> vertical, with one unit of change corresponding roughly to one degree >> of change. > > > Thanks. This appears to me as not the most straight-forward range. I would > expect kernel to report 0-symmetric values. Maybe it's not late to change > that to have better compatibility with generic HID devices? > While I agree that [0, 127] isn't obvious, changing it to be 0-symmetric isn't going to happen any time soon. The X driver unfortunately expects that range -- it doesn't ask the kernel. Any kernel change would have to come quite a while after the X driver was modified to ask the kernel instead (otherwise we risk breaking tilt for anyone with an old Xorg driver)
> >> The Xorg driver centers the data from the kernel about zero >> (resulting in a range [-64, 63]) and reports them for applications in >> the 4th (X tilt) and 5th (Y tilt) valuators. > > > So far I've got evdev to report ABS_TILT_X and ABS_TILT_Y as 4th and 5th > valuators from the kernel as is. So I'll leave the kernel driver reporting > 0-symmetric values for now. It seems the range is already clipped to > [-64,64], although the original report descriptor states [-127,127]. > Is the range of values you get out of the kernel clipped to [-64,64], or is evdev doing the clipping? If the hardware is only sending data in that range there isn't much you can do about it (aside from double-checking that you're reading the tilt packets correctly). Otherwise, I'd make sure the range you tell the kernel to expect is correct -- I hope evdev doesn't have [-64,64] hardcoded, but we do the same thing so.... > Can you suggest a way to test the tilt with a real-world application, not > just "xinput test" or "xev"? > I usually use gimp for real-world testing, though I think you'll only get tilt-sensitivity in gimp-2.7 (which is an unstable release...) > Thanks! > > Sincerely, > Nick Jason --- Day xee-nee-svsh duu-'ushtlh-ts'it; nuu-wee-ya' duu-xan' 'vm-nvshtlh-ts'it. Huu-chan xuu naa~-gha. ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Linuxwacom-devel mailing list Linuxwacom-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxwacom-devel
