tron@zhadum.de said:
> 1.) The old PS/2 driver keeps track of all mouse movements in internal
>     variables and returns a single delta pair on an ioctl() call. 

Are you sure this is actually used by the X server?
(didn't see it, at least at a first glance)

As I see it so far, the mouse handling is quite similar.
I'd suspect the buffer size in xsrc/.../std_mseEv.c to influence
the performance: an opms packet is 3 bytes long; one read
will return quite a number of accumulated mouse movements.
A wsevent is much larger (16 bytes or so), so more context
switches are needed to get the data into the X server.

best regards
Matthias