diff options
Diffstat (limited to 'drivers/input/mouse/synaptics.c')
| -rw-r--r-- | drivers/input/mouse/synaptics.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c index 37033ade79d3..12d12ca3fee0 100644 --- a/drivers/input/mouse/synaptics.c +++ b/drivers/input/mouse/synaptics.c @@ -53,14 +53,19 @@ #define ABS_POS_BITS 13 /* - * Any position values from the hardware above the following limits are - * treated as "wrapped around negative" values that have been truncated to - * the 13-bit reporting range of the hardware. These are just reasonable - * guesses and can be adjusted if hardware is found that operates outside - * of these parameters. + * These values should represent the absolute maximum value that will + * be reported for a positive position value. Some Synaptics firmware + * uses this value to indicate a finger near the edge of the touchpad + * whose precise position cannot be determined. + * + * At least one touchpad is known to report positions in excess of this + * value which are actually negative values truncated to the 13-bit + * reporting range. These values have never been observed to be lower + * than 8184 (i.e. -8), so we treat all values greater than 8176 as + * negative and any other value as positive. */ -#define X_MAX_POSITIVE (((1 << ABS_POS_BITS) + XMAX) / 2) -#define Y_MAX_POSITIVE (((1 << ABS_POS_BITS) + YMAX) / 2) +#define X_MAX_POSITIVE 8176 +#define Y_MAX_POSITIVE 8176 /***************************************************************************** * Stuff we need even when we do not want native Synaptics support @@ -604,11 +609,21 @@ static int synaptics_parse_hw_state(const unsigned char buf[], hw->right = (buf[0] & 0x02) ? 1 : 0; } - /* Convert wrap-around values to negative */ + /* + * Convert wrap-around values to negative. (X|Y)_MAX_POSITIVE + * is used by some firmware to indicate a finger at the edge of + * the touchpad whose precise position cannot be determined, so + * convert these values to the maximum axis value. + */ if (hw->x > X_MAX_POSITIVE) hw->x -= 1 << ABS_POS_BITS; + else if (hw->x == X_MAX_POSITIVE) + hw->x = XMAX; + if (hw->y > Y_MAX_POSITIVE) hw->y -= 1 << ABS_POS_BITS; + else if (hw->y == Y_MAX_POSITIVE) + hw->y = YMAX; return 0; } |