The KdEnqueuePointerEvent cannot work with tslib driver

I am running the Xfbdev on an ARM platform, using the git source and using this command to config:
./autogen.sh --prefix=/arm1/opt/fdo --disable-ipv6 --enable-tslib --enable-kdrive --enable-xfbdev --disable-glx --disable-xorg --disable-xorgcfg --disable-dri --enable-xcalibrate --enable-screensaver

the screensize is 480x272

Use this command to launch the Xfbdev:
./Xfbdev -mouse tslib,3,device=/dev/input/event0

I add some ErrorF in this function, I click two times on the touchscreen:

ErrorF("%s %s flags=0x%x rx=%d ry=%d LastState=0x%x T=%d\n", 
		__FUNCTION__, pi->name, flags, rx, ry, pi->buttonState, pi->transformCoordinates);
		
ErrorF("x=%d y=%d [%d-%d] dixflags=0x%x buttons=0x%x\n", 
		x, y, pi->dixdev->last.valuators[0], pi->dixdev->last.valuators[1], dixflags, flags);		

Below is the debug log

first click:

KdEnqueuePointerEvent Touchscreen flags=0x1 rx=11 ry=261 LastState=0x0 T=1
x=11 y=261 [0-0] dixflags=0x4 buttons=0x1
type=0x6 x=11 y=261 b=0
type=0x4 x=11 y=261 b=1
KdEnqueuePointerEvent Touchscreen flags=0x0 rx=11 ry=261 LastState=0x1 T=1
x=11 y=261 [11-261] dixflags=0x0 buttons=0x0
type=0x5 x=11 y=261 b=1

Second click:

KdEnqueuePointerEvent Touchscreen flags=0x1 rx=62 ry=222 LastState=0x0 T=1
x=62 y=222 [22-271] dixflags=0x4 buttons=0x1
type=0x6 x=62 y=222 b=0
type=0x4 x=62 y=222 b=1
KdEnqueuePointerEvent Touchscreen flags=0x0 rx=62 ry=222 LastState=0x1 T=1
x=62 y=222 [62-222] dixflags=0x0 buttons=0x0
type=0x5 x=62 y=222 b=1

the problem is the last.valuators have wrong values.

On the ButtonPress event, the last.valuators store the X/Y postion value, however, on the ButtonRelease event, it adds the old X/Y postion value. this causes the second click has
wrong [22-271] value