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

[Vojtech Pavlik <vojtech@suse.cz>]

On Sat, Jun 14, 2003 at 05:29:33PM -0700, Eric Wong wrote:

> 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

Thanks for the info. I didn't expect Logitech to ever need more than 16
special packets bits. 

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR