diff --git a/dlls/winealsa.drv/mmdevdrv.c b/dlls/winealsa.drv/mmdevdrv.c
index 236ae40d042..6889b2eb23d 100644
--- a/dlls/winealsa.drv/mmdevdrv.c
+++ b/dlls/winealsa.drv/mmdevdrv.c
@@ -2427,7 +2427,7 @@ static HRESULT WINAPI AudioSessionControl_GetGroupingParam(
 }
 
 static HRESULT WINAPI AudioSessionControl_SetGroupingParam(
-        IAudioSessionControl2 *iface, GUID *group, const GUID *session)
+        IAudioSessionControl2 *iface, const GUID *group, const GUID *session)
 {
     AudioSessionWrapper *This = impl_from_IAudioSessionControl2(iface);
 
diff --git a/dlls/winecoreaudio.drv/mmdevdrv.c b/dlls/winecoreaudio.drv/mmdevdrv.c
index 79c47de1a95..261bb2bed9a 100644
--- a/dlls/winecoreaudio.drv/mmdevdrv.c
+++ b/dlls/winecoreaudio.drv/mmdevdrv.c
@@ -2191,7 +2191,7 @@ static HRESULT WINAPI AudioSessionControl_GetGroupingParam(
 }
 
 static HRESULT WINAPI AudioSessionControl_SetGroupingParam(
-        IAudioSessionControl2 *iface, GUID *group, const GUID *session)
+        IAudioSessionControl2 *iface, const GUID *group, const GUID *session)
 {
     AudioSessionWrapper *This = impl_from_IAudioSessionControl2(iface);
 
diff --git a/dlls/wineoss.drv/mmdevdrv.c b/dlls/wineoss.drv/mmdevdrv.c
index 3d2385f3608..7ff33a990fc 100644
--- a/dlls/wineoss.drv/mmdevdrv.c
+++ b/dlls/wineoss.drv/mmdevdrv.c
@@ -2120,7 +2120,7 @@ static HRESULT WINAPI AudioSessionControl_GetGroupingParam(
 }
 
 static HRESULT WINAPI AudioSessionControl_SetGroupingParam(
-        IAudioSessionControl2 *iface, GUID *group, const GUID *session)
+        IAudioSessionControl2 *iface, const GUID *group, const GUID *session)
 {
     AudioSessionWrapper *This = impl_from_IAudioSessionControl2(iface);
 
diff --git a/include/audiopolicy.idl b/include/audiopolicy.idl
index fad17f5b401..53655bc42c8 100644
--- a/include/audiopolicy.idl
+++ b/include/audiopolicy.idl
@@ -115,7 +115,7 @@ interface IAudioSessionControl : IUnknown
         [out] GUID *pRetVal
     );
     HRESULT SetGroupingParam(
-        [in] GUID *Override,
+        [in] LPCGUID Override,
         [unique,in] LPCGUID EventContext
     );
     HRESULT RegisterAudioSessionNotification(