[Testing] [OLPC-AU] Testing summary - Auckland New Zealand, 5 February 2011

[James Cameron]

On Mon, Feb 07, 2011 at 09:20:24AM +1000, Peter Hewitt wrote:
> Tabitha wrote:
> > The touchpad cursor jerky issues appear ...
> > ... she struggled with jerky cursor, even using a USB mouse."
> 
> This is of great concern to me ... especially the USB mouse ... I test
> on XO-1s .82 & .84 ... though not ideal the cursor movement is ok.

It may help to gain an understanding of what the tester was perceiving.
There are a few possibilities;

- latency between finger move and cursor move,

- cursor not passing through intervening locations, (as compared to how
  the cursor works in other activities),

- cursor not tracking finger.

I speculate that it is the second behaviour that is being observed.

Peter, going technical, sugargame has a python layer translating events
from GTK+ to pygame, and reducing the event load on this layer
(event.py) may help to increase performance to the point that you can
increase the framerate and reduce jerkiness ... the motion events
originate in GTK+, are delivered to the inner event box
(self._inner_evb.set_events()), are connected to the motion-notify-event
handler _mousemove_cb, then if is_hint is true a
gtk.gdk.Window.get_pointer call is made ... this might be a round-trip
request to the X server.  It may be expensive.  You might be able to
alleviate this by removing POINTER_MOTION_HINT_MASK.  I've not tried it
yet.  I'm interested in what you find.

-- 
James Cameron
http://quozl.linux.org.au/