On 13 May 2002 10:37:22, [EMAIL PROTECTED] wrote: > The touchscreen is *NOT* a mouse. It should definately *NOT* > be called /dev/mouse.... It does not return motion: it returns > position, in a funky format that we intend to abolish...
I hope this isn't a general condemnation of touch screens appearing via /dev/mouse. The Semtech ScreenCoder used in the ViewSonic ViewPad 1000 rather tightly couples the interaction of the mouse and touch screen. Upon startup, the touch screen acts as the controller for an external mouse, and generates its own relative motion packets, which it merges with those from the external mouse. In this mode, it's obvious that /dev/mouse (actually /dev/psaux) is appropriate. Upon receipt of a special knocking sequence, the controller shifts to generating absolute mode packets for the touch screen, while preserving relative motion packets from the mouse. On April 11, I submitted a set of patches, one for the 4.2.0 release and one for a CVS extraction done April 8, which generates this knocking sequence and then disambiguates the packets arriving via the interface. So if one wishes to use absolute mode, one simply declares the protocol to be "ScreenCoderPS/2" instead of "PS/2". (One can also use "ScreenCoderIMPS/2" and "ScreenCoderEXPPS/2" instead of "IMPS/2" and "EXPPS/2".) (I'm investigating two enhancements: the first to better control calibration and the second to switch between relative and absolute position mode at run-time. I'll post progress reports later.) Of course if Jim is writing about a touch screen which has a distinct data path to the the computer, what I've written is only remotely tangential to the topic. Randolph Bentson [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
