PATCH: uep(4) support for (my) eGalax touchscreen

[Anthony Jenkins]

I'm trying to add support for uep(4) to detect and properly emit touch
events to x11-drivers/xf86-input-egalax. What I have works, but has some
issues, particularly:

 - close(2)ing the device node causes a USB_ST_ERROR in the
uep_intr_callback(); it's probably from my attempt to port an
initialization control message from Linux
 - I massage the touch events from my device into the legacy uep(4)
event structure since my multitouch-supporting touchscreen has 12-bits
of resolution per axis, but legacy uep(4) only had 11
 - For some reason my Y-axis is inverted; I had to subtract its
coordinate from the max Y value.  I'll probably add an ioctl(2) to set
axis inversion behavior dynamically rather than hardcode it.
 - I capture all the multitouch info from the USB packets, but I don't
know (yet) if xf86-input-egalax can do anything with it
 - x11-drivers/xf86-input-egalax's default min/max ranges are "silly"
(500/1500), but I didn't add the trivial patch to it.  I'd like to add
an ioctl(2) that lets xf86-input-egalax query uep(4) for axis ranges,
but as I've written my patch, uep(4) doesn't know its ranges until it
gets a touch packet.
 - I started adding support for evdev(4) reporting (added header files
and device struct members), but it's nowhere near finished.
 - I have no idea how common this eGalax protocol is or how to determine
what protocol to use from the driver.  Right now I assume a byte 0 of
0x06 means "multitouch event".
 - My x11-servers/xorg-server is patched to associate /dev/uep0 with the
xf86-input-egalax driver; I guess I'll have to make that available too. 
My config/devd.c is substantially different from stock.

Logging is sort of noisy at the moment when touching the screen, but it
"Just Works (TM)" with my touchscreen, my slightly-patched
xf86-input-egalax driver and KDE4.

uep(4) patch:
https://github.com/ScoobiFreeBSD/freebsd/commit/62c11d484d5fb61749240b439612f852c5148222
x11-servers/xorg-server patch:
https://github.com/ScoobiFreeBSD/freebsd-ports/commit/9465237f83ab8fb27249abfe803f94b6b8c3b945

Suggestions/comments welcome.  Currently looking for help with the
USB_ST_ERROR issue, although I think I may know what's wrong (this is my
1st attempt at USB stack programming).

Anthony Jenkins