Synaptics Touchpad uses about 1.1w when moving mouse

[Alan Jenkins]

Scott Mansell wrote:
> While experimenting with getting my laptop's power usage down, I
> discovered that moving the mouse caused a lot of i8042 interrupts
> (with a finger resting on the pad, just under 430 interrupts per
> second (per core? this is a core 2 duo)). With all these interrupts,
> my power usage increased by like 1.1w, which is a lot considering I
> can get it down to around 10.1w.
>
> Apart from not using the touchpad, is there anything I can do to
> decrease the power usage. 480 interrupts seams a little high,
> considering the touchpad is only meant to generate 40 or 80 packets of
> data per second.
>   
Code says the synaptic packetsize is 6 bytes, and the i8042 PS2 
controller delivers each byte in a separate interrupt, so 480 interrupts 
would be consistent with 80 packets.  I suspect there's nothing you can 
do.  My desktop does 500 wakeups/s with continuous mouse movement; I 
don't think this is unusual.

Maybe serial mice are the way to go :-P.  Tho what you gain from the 
FIFO buffering you might lose in powering the serial port, I dunno.  Or 
USB, though that would stop you from going into C3.

Alan