diff --git a/dlls/dinput/device.c b/dlls/dinput/device.c
index 77c0c24b86d..5d8c9549c27 100644
--- a/dlls/dinput/device.c
+++ b/dlls/dinput/device.c
@@ -124,14 +124,14 @@ void _dump_DIPROPHEADER(LPCDIPROPHEADER diph) {
     }
 }
 
-void _dump_OBJECTINSTANCEA(DIDEVICEOBJECTINSTANCEA *ddoi) {
+void _dump_OBJECTINSTANCEA(const DIDEVICEOBJECTINSTANCEA *ddoi) {
     if (TRACE_ON(dinput)) {
         DPRINTF("    - enumerating : %s ('%s') - %2d - 0x%08x - %s\n",
 		debugstr_guid(&ddoi->guidType), _dump_dinput_GUID(&ddoi->guidType), ddoi->dwOfs, ddoi->dwType, ddoi->tszName);
     }
 }
 
-void _dump_OBJECTINSTANCEW(DIDEVICEOBJECTINSTANCEW *ddoi) {
+void _dump_OBJECTINSTANCEW(const DIDEVICEOBJECTINSTANCEW *ddoi) {
     if (TRACE_ON(dinput)) {
         DPRINTF("    - enumerating : %s ('%s'), - %2d - 0x%08x - %s\n",
 		debugstr_guid(&ddoi->guidType), _dump_dinput_GUID(&ddoi->guidType), ddoi->dwOfs, ddoi->dwType, debugstr_w(ddoi->tszName));
@@ -217,7 +217,7 @@ void _dump_DIDATAFORMAT(const DIDATAFORMAT *df) {
 }
 
 /* Conversion between internal data buffer and external data buffer */
-void fill_DataFormat(void *out, const void *in, DataFormat *df) {
+void fill_DataFormat(void *out, const void *in, const DataFormat *df) {
     int i;
     const char *in_c = in;
     char *out_c = (char *) out;
@@ -436,7 +436,7 @@ failed:
 }
 
 /* find an object by it's offset in a data format */
-static int offset_to_object(DataFormat *df, int offset)
+static int offset_to_object(const DataFormat *df, int offset)
 {
     int i;
 
@@ -460,14 +460,14 @@ static int id_to_object(LPCDIDATAFORMAT df, int id)
     return -1;
 }
 
-int id_to_offset(DataFormat *df, int id)
+int id_to_offset(const DataFormat *df, int id)
 {
     int obj = id_to_object(df->wine_df, id);
 
     return obj >= 0 && df->offsets ? df->offsets[obj] : -1;
 }
 
-int find_property(DataFormat *df, LPCDIPROPHEADER ph)
+int find_property(const DataFormat *df, LPCDIPROPHEADER ph)
 {
     switch (ph->dwHow)
     {
diff --git a/dlls/dinput/device_private.h b/dlls/dinput/device_private.h
index f62ad5c9887..4af99cc6645 100644
--- a/dlls/dinput/device_private.h
+++ b/dlls/dinput/device_private.h
@@ -68,13 +68,13 @@ struct IDirectInputDevice2AImpl
 };
 
 /* Routines to do DataFormat / WineFormat conversions */
-extern void fill_DataFormat(void *out, const void *in, DataFormat *df) ;
+extern void fill_DataFormat(void *out, const void *in, const DataFormat *df) ;
 extern HRESULT create_DataFormat(LPCDIDATAFORMAT asked_format, DataFormat *format);
 extern void release_DataFormat(DataFormat *df) ;
 extern void queue_event(LPDIRECTINPUTDEVICE8A iface, int ofs, DWORD data, DWORD time, DWORD seq);
 /* Helper functions to work with data format */
-extern int id_to_offset(DataFormat *df, int id);
-extern int find_property(DataFormat *df, LPCDIPROPHEADER ph);
+extern int id_to_offset(const DataFormat *df, int id);
+extern int find_property(const DataFormat *df, LPCDIPROPHEADER ph);
 
 /**
  * Callback Data used by specific callback 
@@ -92,8 +92,8 @@ extern BOOL DIEnumDevicesCallbackAtoW(LPCDIDEVICEOBJECTINSTANCEA, LPVOID);
 extern void _dump_cooperativelevel_DI(DWORD dwFlags) ;
 extern void _dump_EnumObjects_flags(DWORD dwFlags) ;
 extern void _dump_DIPROPHEADER(LPCDIPROPHEADER diph) ;
-extern void _dump_OBJECTINSTANCEA(DIDEVICEOBJECTINSTANCEA *ddoi) ;
-extern void _dump_OBJECTINSTANCEW(DIDEVICEOBJECTINSTANCEW *ddoi) ;
+extern void _dump_OBJECTINSTANCEA(const DIDEVICEOBJECTINSTANCEA *ddoi) ;
+extern void _dump_OBJECTINSTANCEW(const DIDEVICEOBJECTINSTANCEW *ddoi) ;
 extern void _dump_DIDATAFORMAT(const DIDATAFORMAT *df) ;
 extern const char *_dump_dinput_GUID(const GUID *guid) ;
 
diff --git a/dlls/dinput/effect_linuxinput.c b/dlls/dinput/effect_linuxinput.c
index e9f5604333d..f5851fc678c 100644
--- a/dlls/dinput/effect_linuxinput.c
+++ b/dlls/dinput/effect_linuxinput.c
@@ -118,7 +118,7 @@ static void _dump_DIEFFECT_flags(DWORD dwFlags)
     }       
 }
 
-static void _dump_DIENVELOPE(LPDIENVELOPE env)
+static void _dump_DIENVELOPE(LPCDIENVELOPE env)
 {
     if (env->dwSize != sizeof(DIENVELOPE)) {
         WARN("Non-standard DIENVELOPE structure size (%d instead of %d).\n",
@@ -128,31 +128,31 @@ static void _dump_DIENVELOPE(LPDIENVELOPE env)
 	  env->dwAttackLevel, env->dwAttackTime, env->dwFadeLevel, env->dwFadeTime);
 } 
 
-static void _dump_DICONSTANTFORCE(LPDICONSTANTFORCE frc)
+static void _dump_DICONSTANTFORCE(LPCDICONSTANTFORCE frc)
 {
     TRACE("Constant force has magnitude %d\n", frc->lMagnitude);
 }
 
-static void _dump_DIPERIODIC(LPDIPERIODIC frc)
+static void _dump_DIPERIODIC(LPCDIPERIODIC frc)
 {
     TRACE("Periodic force has magnitude %d, offset %d, phase %d, period %d\n",
 	  frc->dwMagnitude, frc->lOffset, frc->dwPhase, frc->dwPeriod);
 }
 
-static void _dump_DIRAMPFORCE(LPDIRAMPFORCE frc)
+static void _dump_DIRAMPFORCE(LPCDIRAMPFORCE frc)
 {
     TRACE("Ramp force has start %d, end %d\n",
 	  frc->lStart, frc->lEnd);
 }
 
-static void _dump_DICONDITION(LPDICONDITION frc)
+static void _dump_DICONDITION(LPCDICONDITION frc)
 {
     TRACE("Condition has offset %d, pos/neg coefficients %d and %d, pos/neg saturations %d and %d, deadband %d\n",
 	  frc->lOffset, frc->lPositiveCoefficient, frc->lNegativeCoefficient,
 	  frc->dwPositiveSaturation, frc->dwNegativeSaturation, frc->lDeadBand);
 }
 
-static void _dump_DICUSTOMFORCE(LPDICUSTOMFORCE frc)
+static void _dump_DICUSTOMFORCE(LPCDICUSTOMFORCE frc)
 {
     unsigned int i;
     TRACE("Custom force uses %d channels, sample period %d.  Has %d samples at %p.\n",
diff --git a/dlls/dinput/joystick_linux.c b/dlls/dinput/joystick_linux.c
index bc4ef5b5526..50a5f498567 100644
--- a/dlls/dinput/joystick_linux.c
+++ b/dlls/dinput/joystick_linux.c
@@ -120,7 +120,7 @@ static const GUID DInput_Wine_Joystick_GUID = { /* 9e573ed9-7734-11d2-8d4a-23903
   {0x8d, 0x4a, 0x23, 0x90, 0x3f, 0xb6, 0xbd, 0xf7}
 };
 
-static void _dump_DIDEVCAPS(LPDIDEVCAPS lpDIDevCaps)
+static void _dump_DIDEVCAPS(const DIDEVCAPS *lpDIDevCaps)
 {
     TRACE("dwSize: %d\n", lpDIDevCaps->dwSize);
     TRACE("dwFlags: %08x\n", lpDIDevCaps->dwFlags);