>From 883cab39ace28695c3be4303b919d3b786d83ee6 Mon Sep 17 00:00:00 2001
From: Simon Thum <simon.thum@gmx.de>
Date: Tue, 28 Apr 2009 10:11:32 +0200
Subject: [PATCH] dix: add 'none' pointer acceleration profile with number -1

this is a shorthand for disabling acceleration, while retaining the
possiblity to use constant deceleration. If constant deceleration is
unused, it will also optimize motion processing.
---
 dix/ptrveloc.c     |   30 ++++++++++++++++++++++++------
 include/ptrveloc.h |    4 ++--
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/dix/ptrveloc.c b/dix/ptrveloc.c
index 1590cfd..6553772 100644
--- a/dix/ptrveloc.c
+++ b/dix/ptrveloc.c
@@ -80,9 +80,12 @@ GetAccelerationProfile(DeviceVelocityPtr s, int profile_num);
 #endif
 
 /********************************
- *  Init/Uninit etc
+ *  Init/Uninit
  *******************************/
 
+/* some int which is not a profile number */
+#define PROFILE_UNINITIALIZE (-100)
+
 /**
  * Init struct so it should match the average case
  */
@@ -111,7 +114,7 @@ InitVelocityData(DeviceVelocityPtr s)
 static void
 FreeVelocityData(DeviceVelocityPtr s){
     xfree(s->tracker);
-    SetAccelerationProfile(s, -1);
+    SetAccelerationProfile(s, PROFILE_UNINITIALIZE);
 }
 
 
@@ -827,6 +830,16 @@ LinearProfile(
 }
 
 
+static float
+NoProfile(
+    DeviceVelocityPtr pVel,
+    float velocity,
+    float threshold,
+    float acc)
+{
+    return 1.0f;
+}
+
 static PointerAccelerationProfileFunc
 GetAccelerationProfile(
     DeviceVelocityPtr s,
@@ -847,8 +860,8 @@ GetAccelerationProfile(
             return PowerProfile;
         case AccelProfileLinear:
             return LinearProfile;
-        case AccelProfileReserved:
-            /* reserved for future use, e.g. a user-defined profile */
+        case AccelProfileNone:
+            return NoProfile;
         default:
             return NULL;
     }
@@ -859,7 +872,7 @@ GetAccelerationProfile(
  * Intended to make profiles exchangeable at runtime.
  * If you created a profile, give it a number here and in the header to
  * make it selectable. In case some profile-specific init is needed, here
- * would be a good place, since FreeVelocityData() also calls this with -1.
+ * would be a good place, since FreeVelocityData() also calls this with -100.
  * returns FALSE (0) if profile number is unavailable.
  */
 int
@@ -870,7 +883,7 @@ SetAccelerationProfile(
     PointerAccelerationProfileFunc profile;
     profile = GetAccelerationProfile(s, profile_num);
 
-    if(profile == NULL && profile_num != -1)
+    if(profile == NULL && profile_num != PROFILE_UNINITIALIZE)
 	return FALSE;
 
     if(s->profile_private != NULL){
@@ -958,6 +971,11 @@ acceleratePointerPredictable(
     if (!num_valuators || !valuators || !velocitydata)
         return;
 
+    if (velocitydata->statistics.profile_number == AccelProfileNone &&
+	velocitydata->const_acceleration == 1.0f) {
+	return; /*we're inactive anyway, so skip the whole thing.*/
+    }
+
     if (first_valuator == 0) {
         dx = valuators[0];
         px = &valuators[0];
diff --git a/include/ptrveloc.h b/include/ptrveloc.h
index 6ef8c75..974af35 100644
--- a/include/ptrveloc.h
+++ b/include/ptrveloc.h
@@ -27,9 +27,9 @@
 
 #include <input.h> /* DeviceIntPtr */
 
-/* constants for acceleration profiles;
- * see  */
+/* constants for acceleration profiles */
 
+#define AccelProfileNone -1
 #define AccelProfileClassic  0
 #define AccelProfileDeviceSpecific 1
 #define AccelProfilePolynomial 2
-- 
1.6.0.6