Hello, IBM Trackpoints have a feature to compensate for drift by recalibrating themselves periodically. If for 0.5 seconds there is no change in position, it uses this as the new zero. This happens often when the trackpoint is in fact being used. This is frustrating. Raising the time solves the problem. IBM's Trackpoint Engineering Specifications offer a configuration register for this (rstdft1). It just needs to be exposed by the driver, as others already are. Cheers! -Mike IBM Trackpoints have a feature to compensate for drift by recalibrating themselves periodically. By default, if for 0.5 seconds there is no change in position, it's used as the new zero. This duration is too low. Often, the calibration happens when the trackpoint is in fact being used. IBM's Trackpoint Engineering Specifications show a configuration register that allows changing this duration, rstdft1. Expose it via sysfs among the other settings. Signed-off-by: Mike Murdoch <main.haarp@xxxxxxxxx> --- a/drivers/input/mouse/trackpoint.h 2014-12-06 13:12:34.167917741 +0100 +++ b/drivers/input/mouse/trackpoint.h 2014-12-08 19:17:46.241131557 +0100 @@ -70,6 +70,9 @@ #define TP_UP_THRESH 0x5A /* Used to generate a 'click' on Z-axis */ #define TP_Z_TIME 0x5E /* How sharp of a press */ #define TP_JENKS_CURV 0x5D /* Minimum curvature for double click */ +#define TP_DRIFT_TIME 0x5F /* How long a 'hands off' condition */ + /* must last (x*107ms) for drift */ + /* correction to occur */ /* * Toggling Flag bits @@ -120,6 +123,7 @@ #define TP_DEF_UP_THRESH 0xFF #define TP_DEF_Z_TIME 0x26 #define TP_DEF_JENKS_CURV 0x87 +#define TP_DEF_DRIFT_TIME 0x05 /* Toggles */ #define TP_DEF_MB 0x00 @@ -137,6 +141,7 @@ struct trackpoint_data unsigned char draghys, mindrag; unsigned char thresh, upthresh; unsigned char ztime, jenks; + unsigned char drift_time; /* toggles */ unsigned char press_to_select; --- a/drivers/input/mouse/trackpoint.c 2014-12-06 13:12:34.167917741 +0100 +++ b/drivers/input/mouse/trackpoint.c 2014-12-06 16:03:09.587952302 +0100 @@ -227,6 +227,7 @@ TRACKPOINT_INT_ATTR(thresh, TP_THRESH, T TRACKPOINT_INT_ATTR(upthresh, TP_UP_THRESH, TP_DEF_UP_THRESH); TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME, TP_DEF_Z_TIME); TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV, TP_DEF_JENKS_CURV); +TRACKPOINT_INT_ATTR(drift_time, TP_DRIFT_TIME, TP_DEF_DRIFT_TIME); TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, 0, TP_DEF_PTSON); @@ -249,6 +250,7 @@ static struct attribute *trackpoint_attr &psmouse_attr_press_to_select.dattr.attr, &psmouse_attr_skipback.dattr.attr, &psmouse_attr_ext_dev.dattr.attr, + &psmouse_attr_drift_time.dattr.attr, NULL }; @@ -312,6 +314,7 @@ static int trackpoint_sync(struct psmous TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, upthresh); TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ztime); TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, jenks); + TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, drift_time); /* toggles */ TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, press_to_select); @@ -333,6 +336,7 @@ static void trackpoint_defaults(struct t TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ztime); TRACKPOINT_SET_POWER_ON_DEFAULT(tp, jenks); TRACKPOINT_SET_POWER_ON_DEFAULT(tp, inertia); + TRACKPOINT_SET_POWER_ON_DEFAULT(tp, drift_time); /* toggles */ TRACKPOINT_SET_POWER_ON_DEFAULT(tp, press_to_select);
IBM Trackpoints have a feature to compensate for drift by recalibrating themselves periodically. By default, if for 0.5 seconds there is no change in position, it's used as the new zero. This duration is too low. Often, the calibration happens when the trackpoint is in fact being used. IBM's Trackpoint Engineering Specifications show a configuration register that allows changing this duration, rstdft1. Expose it via sysfs among the other settings. Signed-off-by: Mike Murdoch <main.haarp@xxxxxxxxx> --- a/drivers/input/mouse/trackpoint.h 2014-12-06 13:12:34.167917741 +0100 +++ b/drivers/input/mouse/trackpoint.h 2014-12-08 19:17:46.241131557 +0100 @@ -70,6 +70,9 @@ #define TP_UP_THRESH 0x5A /* Used to generate a 'click' on Z-axis */ #define TP_Z_TIME 0x5E /* How sharp of a press */ #define TP_JENKS_CURV 0x5D /* Minimum curvature for double click */ +#define TP_DRIFT_TIME 0x5F /* How long a 'hands off' condition */ + /* must last (x*107ms) for drift */ + /* correction to occur */ /* * Toggling Flag bits @@ -120,6 +123,7 @@ #define TP_DEF_UP_THRESH 0xFF #define TP_DEF_Z_TIME 0x26 #define TP_DEF_JENKS_CURV 0x87 +#define TP_DEF_DRIFT_TIME 0x05 /* Toggles */ #define TP_DEF_MB 0x00 @@ -137,6 +141,7 @@ struct trackpoint_data unsigned char draghys, mindrag; unsigned char thresh, upthresh; unsigned char ztime, jenks; + unsigned char drift_time; /* toggles */ unsigned char press_to_select; --- a/drivers/input/mouse/trackpoint.c 2014-12-06 13:12:34.167917741 +0100 +++ b/drivers/input/mouse/trackpoint.c 2014-12-06 16:03:09.587952302 +0100 @@ -227,6 +227,7 @@ TRACKPOINT_INT_ATTR(thresh, TP_THRESH, T TRACKPOINT_INT_ATTR(upthresh, TP_UP_THRESH, TP_DEF_UP_THRESH); TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME, TP_DEF_Z_TIME); TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV, TP_DEF_JENKS_CURV); +TRACKPOINT_INT_ATTR(drift_time, TP_DRIFT_TIME, TP_DEF_DRIFT_TIME); TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, 0, TP_DEF_PTSON); @@ -249,6 +250,7 @@ static struct attribute *trackpoint_attr &psmouse_attr_press_to_select.dattr.attr, &psmouse_attr_skipback.dattr.attr, &psmouse_attr_ext_dev.dattr.attr, + &psmouse_attr_drift_time.dattr.attr, NULL }; @@ -312,6 +314,7 @@ static int trackpoint_sync(struct psmous TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, upthresh); TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ztime); TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, jenks); + TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, drift_time); /* toggles */ TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, press_to_select); @@ -333,6 +336,7 @@ static void trackpoint_defaults(struct t TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ztime); TRACKPOINT_SET_POWER_ON_DEFAULT(tp, jenks); TRACKPOINT_SET_POWER_ON_DEFAULT(tp, inertia); + TRACKPOINT_SET_POWER_ON_DEFAULT(tp, drift_time); /* toggles */ TRACKPOINT_SET_POWER_ON_DEFAULT(tp, press_to_select);
