[Gpm] Synaptics touchpad

[Chris Collins]

> In short, the pc_keyb.c mouse driver is a generic driver.  It is the
> lowest level in the kernel which communicates with the touch pad.
> Gpm, is a 'user-level' (e.g. it runs in user space), in effect sitting
> on top of pc_keyb.c.
> 
> The kernel driver gets bytes from the touch pad and buffers them
> until a client process (gpm) reads them via the read() system call.
> Gpm, reads the incoming bytes from the driver.  It then builds and
> Gpm_Event structures which client processes (e.g. X11) use to
> determine mousy movements.

There are some weird problems with the touchpad in compaq
laptops and one other brand whose name escapes me.

Alan Cox has been working on the issue and he claims
there is now a new kernel level repair n 2.2.18 which addresses
this weirdness so touchpads will not have the 'jumpy mouse'
problem.  How is the GPM interface between the kernel data
and the GPM client process updated when changes in kernel-level 
mouse data occur?

The 2.2.18 is in 'pre' status, but as soon as it is released
I am going to run the raw (unpatched) kernel and test
mouse functionality.

The GPM synaptics.c authors may want to look at the kernel
updates in 2.2.18

--Chris