Re: [PATCH] Logitech PS/2++ updates

[Eric Wong <normalperson@yhbt.net>]

Vojtech Pavlik <vojtech@suse.cz> wrote:
> On Tue, Mar 25, 2003 at 06:55:38PM -0800, Eric Wong wrote:
> >  /*
> >   * The PS2++ protocol is a little bit complex
> >   */
> > +	if (psmouse->type == PSMOUSE_PS2PP) { 
> > +
> > +		if ((packet[0] & 0x48) == 0x48 && (packet[1] & 0x02) == 0x02 ) {
> >  
> 
> Hmm, is this change needed? This
> 
> if ((packet[0] & 0x40) == 0x40 && abs((int)packet[1] - (((int)packet[0] & 0x10) << 4)) > 191 ) {
> 
> condition is from Logitech docs and should work with any PS2PP device.
> It doesn't with yours?

The updated PS2PP uses 6 bits to determine packet-type instead of 4 as
used previously, so compatibility with the touchpad protocol was broken
if I recall correctly.

NEW (6 t bits):
       bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
packet0   E    1   t5   t4    1    M    R    L   
packet1  t3   t2   t1   t0   d2   d1    1    0  
packet2  d8   d7   d6   d5   d4   d3   d2   d1 

OLD (4 t bits)
       bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
packet0   E    1   t3   t2    1    M    R    L   
packet1   ?    ?   t1   t0   d2   d1    1    0  
packet2  d8   d7   d6   d5   d4   d3   d2   d1 

E is set if it's an external device

-- 
Eric Wong