www.nico.schottelius.org/software/gpm/browse_source/gpm-1.99.2.2/patches/1.20.1/rodney-wheel-patch-1.99.2.1.txt

diff -aurp gpm-1.99.2.1-orig/src/daemon/processmouse.c gpm-1.99.2.1/src/daemon/processmouse.c
--- gpm-1.99.2.1-orig/src/daemon/processmouse.c	2008-02-23 06:05:03.000000000 +1100
+++ gpm-1.99.2.1/src/daemon/processmouse.c	2008-03-14 21:30:32.000000000 +1100
@@ -159,7 +159,11 @@ int processMouse(int fd, Gpm_Event *even
    /* up and down, up and down, ... who does a do..while(0) loop ???
       and then makes a break into it... argh ! */
 
-   if (!event->dx && !event->dy && (event->buttons==oldB))
+   /* rodney 13/mar/2008 wheel movement similar to mouse movement
+    * must also be excluded from time (click) processing */
+   if (!event->dx && !event->dy
+       && !event->wdx  && !event->wdy
+       && (event->buttons==oldB) )
       do { /* so to break */
          static long awaketime;
          /*
diff -aurp gpm-1.99.2.1-orig/src/headers/daemon.h gpm-1.99.2.1/src/headers/daemon.h
--- gpm-1.99.2.1-orig/src/headers/daemon.h	2008-02-23 06:05:03.000000000 +1100
+++ gpm-1.99.2.1/src/headers/daemon.h	2008-03-14 21:36:17.000000000 +1100
@@ -60,8 +60,10 @@ typedef struct Gpm_Type {
    char              *name;
    char              *desc;      /* a descriptive line */
    char              *synonyms;  /* extra names (the XFree name etc) as a list */
+   /* mouse specific event handler: */
    int               (*fun)(Gpm_Event *state, unsigned char *data);
 
+   /* mouse specific initialisation function: */
    struct Gpm_Type   *(*init)(int fd, unsigned short flags,
                      struct Gpm_Type   *type, int argc, char **argv);
 
diff -aurp gpm-1.99.2.1-orig/src/headers/gpm.h gpm-1.99.2.1/src/headers/gpm.h
--- gpm-1.99.2.1-orig/src/headers/gpm.h	2008-02-23 06:05:03.000000000 +1100
+++ gpm-1.99.2.1/src/headers/gpm.h	2008-03-14 21:32:49.000000000 +1100
@@ -70,6 +70,17 @@ extern "C" {
 #define GPM_NODE_FIFO     _PATH_DEV	"gpmdata"
 
 /*....................................... Cfg buttons */
+/* Each button has one bit in the 16 bit buttons field.
+ * Mouse movement and wheel movement are not associated with a button
+ * i.e. buttons=GPM_B_NONE in these cases
+ * (except for ms3 mouse, for reasons unknown?)
+ * The middle button if pressed down (or clicked) is independent of 
+ *  the wheel "device" which it happens to be associated with
+ * The use of GPM_B_UP/DOWN with ms3 is unclear. Maybe the wheel 
+ * could be rolled forward then backward
+ * and this would generate a 'click' event on 'button 5' GPM_B_UP,
+ * but really the expected behaviour of wheel is movement, typically
+ * used for jump scrolling or for jumping between fields on a form. */
 
 #define GPM_B_DOWN      32
 #define GPM_B_UP        16
@@ -124,10 +135,17 @@ enum Gpm_Margin {GPM_TOP=1, GPM_BOT=2, G
 typedef struct Gpm_Event {
   unsigned char buttons, modifiers;  /* try to be a multiple of 4 */
   unsigned short vc;
-  short dx, dy, x, y;
+  short dx, dy, x, y; /* displacement x,y for this event, and absolute x,y */
   enum Gpm_Etype type;
+  /* clicks e.g. double click are determined by time-based processing */
   int clicks;
   enum Gpm_Margin margin;
+  /* wdx/y: displacement of wheels in this event. Absolute values are not 
+   * required, because wheel movement is typically used for scrolling
+   * or selecting fields, not for cursor positioning. The application
+   * can determine when the end of file or form is reached, and not
+   * go any further. 
+   * A single mouse will use wdy, "vertical scroll" wheel. */
   short wdx, wdy;
 }              Gpm_Event;
 
diff -aurp gpm-1.99.2.1-orig/src/lib/liblow.c gpm-1.99.2.1/src/lib/liblow.c
--- gpm-1.99.2.1-orig/src/lib/liblow.c	2008-02-23 06:05:03.000000000 +1100
+++ gpm-1.99.2.1/src/lib/liblow.c	2008-03-14 21:44:12.000000000 +1100
@@ -198,7 +198,7 @@ int Gpm_Open(Gpm_Connect *conn, int flag
    char* sock_name = 0;
    static char *consolename = NULL;
 
-   gpm_report(GPM_PR_DEBUG,"VC: %d",flag);
+   // gpm_report(GPM_PR_DEBUG,"VC: %d",flag);
 
    /*....................................... First of all, check xterm */
 
diff -aurp gpm-1.99.2.1-orig/src/mice.c gpm-1.99.2.1/src/mice.c
--- gpm-1.99.2.1-orig/src/mice.c	2008-02-23 06:05:03.000000000 +1100
+++ gpm-1.99.2.1/src/mice.c	2008-03-14 21:39:42.000000000 +1100
@@ -552,9 +552,10 @@ static int R_imps2(Gpm_Event *state, int
       (dy > 0 ? 0x20 : 0);
    buffer[1] = dx & 0xFF;
    buffer[2] = (-dy) & 0xFF;
-   buffer[3] = 
-      (state->buttons & GPM_B_UP ? -1 : 0) + 
-      (state->buttons & GPM_B_DOWN ? 1 : 0);
+   if (state->wdy > 0) buffer[3] = 0xff;
+   if (state->wdy < 0) buffer[3] = 0x01;
+   if (state->wdx > 0) buffer[3] = 0xfe;
+   if (state->wdx < 0) buffer[3] = 0x02;
   
    return write(fd,buffer,4);
 
@@ -651,20 +652,25 @@ static int M_imps2(Gpm_Event *state,  un
    state->dy = (data[0] & 0x20) ? -(data[2] - 256) : -data[2];
    
    /* The wheels.. */
-   switch (data[3] & 0x0f) {
-      case 0x0e: state->wdx = +1; break;
-      case 0x02: state->wdx = -1; break;
-      case 0x0f: state->wdy = +1; break;
-      case 0x01: state->wdy = -1; break;
+   unsigned char wheel = data[3] & 0x0f;
+   if (wheel > 0) {
+     // use the event type GPM_MOVE rather than GPM_DOWN for wheel movement
+     // to avoid single/double/triple click processing:
+     switch (wheel) {
+       /* rodney 13/mar/2008
+        * The use of GPM_B_UP / GPM_B_DOWN is very unclear; 
+        *  only mouse type ms3 uses these
+        * For this mouse, we only support the relative movement
+        * i.e. no button is set (same as mouse movement), wdy changes +/-
+        *  according to wheel movement (+ for rolling away from user)
+        * wdx (horizontal scroll) is for a second wheel. They do exist! */
+        case 0x0f: state->wdy = +1; break;
+        case 0x01: state->wdy = -1; break;
+        case 0x0e: state->wdx = +1; break;
+        case 0x02: state->wdx = -1; break;
+     }
    }
-   
-   /* old code:
-      - did it signed: 
-   state->buttons |= (data[3]<0) * GPM_B_UP + (data[3]>0) * GPM_B_DOWN;
-      - and unsigned:
-   state->buttons |= (data[3]>127) * GPM_B_UP + (data[3]<127) * GPM_B_DOWN;
-   */
-    
+
    return 0;
 
 }