On Fri, May 18, 2012 at 10:00:24AM -0500, Seth Forshee wrote: > The synaptics touchpad on the Acer Aspire One D250 will report y > coordinate values in excess of 8000 near the bottom of the touchpad, > well outside of the range of values that the synaptics documentation > says should be reported. > > In addition, the y values abruptly change from very low values to these > very high values. After the calculation to invert the y coordinates, > userspace gets y coordinates that can jump suddenly between large > positive and moderately large negative values, causing sudden jumps in > the pointer position. > > To work around this odd behavior, reject any coordinates with values > outside of absolute limits specified by Synaptics, which is 6143 for > both axes. > > BugLink: http://bugs.launchpad.net/bugs/1001251 > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > --- > I'm not sure whether the limits here should be the hard-coded value or > the coordinates reported by the device when that's supported (i.e. > whether the coordinates reported by the device are always within the > range of 0 to 6143). If the latter is more appropriate I can modify the > patch to use the device-reported values and fall back to the hard-coded > values. Dmitry, Is there someone else I should Cc who might know the answer? Thanks, Seth > > drivers/input/mouse/synaptics.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c > index e07eb9b..f62299d 100644 > --- a/drivers/input/mouse/synaptics.c > +++ b/drivers/input/mouse/synaptics.c > @@ -40,6 +40,8 @@ > * Note that newer firmware allows querying device for maximum useable > * coordinates. > */ > +#define XMAX 6143 > +#define YMAX 6143 > #define XMIN_NOMINAL 1472 > #define XMAX_NOMINAL 5472 > #define YMIN_NOMINAL 1408 > @@ -555,6 +557,9 @@ static int synaptics_parse_hw_state(const unsigned char buf[], > hw->right = (buf[0] & 0x02) ? 1 : 0; > } > > + if (hw->x > XMAX || hw->y > YMAX) > + return 1; > + > return 0; > } > > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
