[PATCH] to "Disable Trackpad while typing" patch

[Torsten Foertsch]

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see http://marc.theaimsgroup.com/?l=linux-kernel&m=105182586512456&w=2

I have encountered problems with that patch. If the mouse is sending events 
while the delay timeout is being reached X11 reports spurious mouse events. 
I.e. you are moving the mouse continuously after hitting a key. My mouse 
often jumps to the right upper corner of the screen and reports some clicks 
there.

Mouse events consist of sequences of 3-4 bytes (normal PS/2 mouses 3 bytes, 
wheel mouses 4 bytes) see
  http://panda.cs.ndsu.nodak.edu/%7Eachapwes/PICmicro/mouse/mouse.html

But with the original patch the first accepted bytes after the timeout can be 
out of that order. So, X11 reads the 2nd or 3rd byte of the actual mouse 
movement as 1st byte.

The patch below implements 2 solutions for the problem:

1. If TRACKPAD_RESET_IF_ACTIVITY_DURING_DELAY is defined it sends a RESET 
command to the mouse after the timeout if there were mouse events during the 
delay interval.

2. If TRACKPAD_RESET_IF_ACTIVITY_DURING_DELAY is not defined it skips chunks 
of 3*4=12 bytes of mouse input.

I am not certain what the "right" solution is. Case 2 is the better one in my 
opinion because after a RESET even a wheel mouse will be in "normal" mode 
sending 3 bytes per event. Further case 2 seems to be more responsive.

Torsten

- --- drivers/char/pc_keyb.c.orig	2003-06-20 08:10:41.000000000 +0000
+++ drivers/char/pc_keyb.c	2003-06-20 15:45:01.000000000 +0000
@@ -18,6 +18,9 @@
  * notebooks with a PS/2 trackpad.
  * Hans-Georg Thien <[e-mail]> 2003-04-30.
  *
+ * Improvements to the "disable trackpad while typing" feature.
+ * Torsten Förtsch <[e-mail]> 2003-06-20.
+ *
  */
 
 #include <linux/config.h>
@@ -109,6 +112,11 @@
 
 #ifdef CONFIG_DISABLE_TRACKPAD_WHILE_TYPING
 
+# ifdef TRACKPAD_RESET_IF_ACTIVITY_DURING_DELAY
+static int trackpad_activity_during_delay = 0;
+# else
+static int trackpad_skipped_events = 0;
+# endif
 static int last_kbd_event = 0;     /* timestamp of last kbd event */
 static int last_kbd_scancode = 0; 
 static int trackpad_disable = 0;
@@ -566,7 +574,12 @@
 		mouse_reply_expected = 0;
 	}
 	else if(scancode == AUX_RECONNECT2 && prev_code == AUX_RECONNECT1
- -		&& aux_reconnect) {
+# ifdef TRACKPAD_RESET_IF_ACTIVITY_DURING_DELAY
+		&& (aux_reconnect||trackpad_activity_during_delay)
+# else
+		&& aux_reconnect
+# endif
+		) {
 		printk (KERN_INFO "PS/2 mouse reconnect detected\n");
 		queue->head = queue->tail = 0;	/* Flush input queue */
 		__aux_write_ack(AUX_ENABLE_DEV);  /* ping the mouse :) */
@@ -577,8 +590,25 @@
         if (trackpad_disable) return;
 
         if (!test_bit(last_kbd_scancode, trackpad_escape)) {
- -                  /* do nothing if time since last kbd event is less then 
trackpad_delay */
- -                  if (abs(jiffies - last_kbd_event) < trackpad_delay) return;
+	  /* do nothing if time since last kbd event is less then trackpad_delay */
+# ifdef TRACKPAD_RESET_IF_ACTIVITY_DURING_DELAY
+	  if (abs(jiffies - last_kbd_event) < trackpad_delay) {
+	    trackpad_activity_during_delay=1;
+	    return;
+	  }
+	  if( trackpad_activity_during_delay ) {
+	    trackpad_activity_during_delay=0;
+	    aux_write_ack(AUX_RESET);
+	    return;
+	  }
+# else
+	  if (abs(jiffies - last_kbd_event) < trackpad_delay ||
+	      trackpad_skipped_events%12) {
+	    trackpad_skipped_events++;
+	    return;
+	  }
+	  trackpad_skipped_events=0;
+# endif
         }
 #endif
 
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