Re: [patch] add module parameter to provide hardware-calibrated coordinate data for MicroTouch/3M touchscreens

Ok - I'll update the patch to invert Y before reporting.

On the issue of whether to use a module param to send raw coordinates
or hw-calibrated coordinates, or to just change the code to report the
hw-calibrated coordinates instead of the raw coordinates, what do you
think?

On Fri, Nov 14, 2008 at 4:31 PM, Vojtech Pavlik [off-list ref] wrote:

On Thu, Nov 13, 2008 at 03:22:52PM -0500, Dan Streetman wrote:

quoted

Note that the Y axis is inverted as reported by the touchscreen, so
this reverses the Y min and max (0xffff for the min, 0 for the max).
This works fine on my system using the X evdev driver.

quoted

+     // Default min/max xy are the raw values, override if using hw-calib
+     if (hwcalib_xy) {
+             input_set_abs_params(usbtouch->input, ABS_X, 0, 0xffff, 0, 0);
+             input_set_abs_params(usbtouch->input, ABS_Y, 0xffff, 0, 0, 0);

While it does work with the X evdev, please don't do it, and instead do
the inversion before reporting ABS_Y. Linux input devices should follow
the (USB) HID specification of axis direction and stick to it. The
behaviour with reversed min/max is undefined.

--
Vojtech Pavlik
Director SuSE Labs