diff options
| author | Chase Douglas <chase.douglas@canonical.com> | 2012-02-09 16:22:35 -0800 |
|---|---|---|
| committer | Chase Douglas <chase.douglas@canonical.com> | 2012-03-02 12:07:49 -0800 |
| commit | f8a73c54b4cb5116c6e23d646bae0ea5061debfc (patch) | |
| tree | 8566df83a4dcf951250f016c3fd17b7bf8041104 | |
| parent | 7969af1e7b8a087bf2a6480a859abcc19bdf71ce (diff) | |
Don't use linear regression when calculating touchpad motion deltas
The results depend on the data rate of the device. A device with a
higher data rate, and thus lower individual deltas, will behave
differently with the regression calculation.
This can be verified on Synaptics semi-mt clickpads. The data rate is
halved when two or more touches are on the device. When trying to press
a button and drag the cursor with another touch, the motion will feel
faster than dragging with only one touch on the device.
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
| -rw-r--r-- | src/synaptics.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/src/synaptics.c b/src/synaptics.c index 202ae9b..e80dff8 100644 --- a/src/synaptics.c +++ b/src/synaptics.c @@ -2163,9 +2163,8 @@ get_delta(SynapticsPrivate *priv, const struct SynapticsHwState *hw, int x_edge_speed = 0; int y_edge_speed = 0; - /* HIST is full enough: priv->count_packet_finger > 3 */ - *dx = estimate_delta(hw->x, HIST(0).x, HIST(1).x, HIST(2).x); - *dy = estimate_delta(hw->y, HIST(0).y, HIST(1).y, HIST(2).y); + *dx = hw->x - HIST(0).x; + *dy = hw->y - HIST(0).y; if ((priv->tap_state == TS_DRAG) || para->edge_motion_use_always) get_edge_speed(priv, hw, edge, &x_edge_speed, &y_edge_speed); @@ -2234,7 +2233,7 @@ ComputeDeltas(SynapticsPrivate *priv, const struct SynapticsHwState *hw, * POLL_MS declaration. */ delay = MIN(delay, POLL_MS); - if (priv->count_packet_finger <= 3) /* min. 3 packets, see get_delta() */ + if (priv->count_packet_finger <= 1) goto out; /* skip the lot */ if (priv->moving_state == MS_TRACKSTICK) |