diff --git a/dlls/wineps.drv/driver.c b/dlls/wineps.drv/driver.c
index 8ec51a29054..ef255b709a2 100644
--- a/dlls/wineps.drv/driver.c
+++ b/dlls/wineps.drv/driver.c
@@ -45,7 +45,7 @@ static inline int paper_size_from_points( float size )
     return size * 254 / 72;
 }
 
-INPUTSLOT *find_slot( PPD *ppd, PSDRV_DEVMODE *dm )
+INPUTSLOT *find_slot( PPD *ppd, const PSDRV_DEVMODE *dm )
 {
     INPUTSLOT *slot;
 
@@ -56,7 +56,7 @@ INPUTSLOT *find_slot( PPD *ppd, PSDRV_DEVMODE *dm )
     return NULL;
 }
 
-PAGESIZE *find_pagesize( PPD *ppd, PSDRV_DEVMODE *dm )
+PAGESIZE *find_pagesize( PPD *ppd, const PSDRV_DEVMODE *dm )
 {
     PAGESIZE *page;
 
@@ -67,7 +67,7 @@ PAGESIZE *find_pagesize( PPD *ppd, PSDRV_DEVMODE *dm )
     return NULL;
 }
 
-DUPLEX *find_duplex( PPD *ppd, PSDRV_DEVMODE *dm )
+DUPLEX *find_duplex( PPD *ppd, const PSDRV_DEVMODE *dm )
 {
     DUPLEX *duplex;
     WORD win_duplex = dm->dmPublic.dmFields & DM_DUPLEX ? dm->dmPublic.dmDuplex : 0;
@@ -88,7 +88,7 @@ DUPLEX *find_duplex( PPD *ppd, PSDRV_DEVMODE *dm )
  * Updates dm1 with some fields from dm2
  *
  */
-void PSDRV_MergeDevmodes( PSDRV_DEVMODE *dm1, PSDRV_DEVMODE *dm2, PRINTERINFO *pi )
+void PSDRV_MergeDevmodes( PSDRV_DEVMODE *dm1, const PSDRV_DEVMODE *dm2, PRINTERINFO *pi )
 {
     /* some sanity checks here on dm2 */
 
diff --git a/dlls/wineps.drv/init.c b/dlls/wineps.drv/init.c
index 2a7c90d20e8..5439ff533d4 100644
--- a/dlls/wineps.drv/init.c
+++ b/dlls/wineps.drv/init.c
@@ -324,7 +324,7 @@ static BOOL PSDRV_CreateDC( PHYSDEV *pdev, LPCWSTR driver, LPCWSTR device,
     if (output && *output) physDev->job.output = strdupW( output );
 
     if(initData)
-        PSDRV_MergeDevmodes(physDev->Devmode, (PSDRV_DEVMODE *)initData, pi);
+        PSDRV_MergeDevmodes(physDev->Devmode, (const PSDRV_DEVMODE *)initData, pi);
 
     PSDRV_UpdateDevCaps(physDev);
     SelectObject( (*pdev)->hdc, PSDRV_DefaultFont );
@@ -379,7 +379,7 @@ static HDC PSDRV_ResetDC( PHYSDEV dev, const DEVMODEW *lpInitData )
 
     if (lpInitData)
     {
-        PSDRV_MergeDevmodes(physDev->Devmode, (PSDRV_DEVMODE *)lpInitData, physDev->pi);
+        PSDRV_MergeDevmodes(physDev->Devmode, (const PSDRV_DEVMODE *)lpInitData, physDev->pi);
         PSDRV_UpdateDevCaps(physDev);
     }
     return dev->hdc;
diff --git a/dlls/wineps.drv/psdrv.h b/dlls/wineps.drv/psdrv.h
index 12ce5269ab8..ffae32854f3 100644
--- a/dlls/wineps.drv/psdrv.h
+++ b/dlls/wineps.drv/psdrv.h
@@ -409,9 +409,9 @@ extern HINSTANCE PSDRV_hInstance DECLSPEC_HIDDEN;
 extern HANDLE PSDRV_Heap DECLSPEC_HIDDEN;
 extern char *PSDRV_ANSIVector[256] DECLSPEC_HIDDEN;
 
-extern INPUTSLOT *find_slot( PPD *ppd, PSDRV_DEVMODE *dm );
-extern PAGESIZE *find_pagesize( PPD *ppd, PSDRV_DEVMODE *dm );
-extern DUPLEX *find_duplex( PPD *ppd, PSDRV_DEVMODE *dm );
+extern INPUTSLOT *find_slot( PPD *ppd, const PSDRV_DEVMODE *dm );
+extern PAGESIZE *find_pagesize( PPD *ppd, const PSDRV_DEVMODE *dm );
+extern DUPLEX *find_duplex( PPD *ppd, const PSDRV_DEVMODE *dm );
 
 /* GDI driver functions */
 extern BOOL PSDRV_Arc( PHYSDEV dev, INT left, INT top, INT right, INT bottom,
@@ -462,7 +462,7 @@ extern INT PSDRV_StartDoc( PHYSDEV dev, const DOCINFOW *doc ) DECLSPEC_HIDDEN;
 extern BOOL PSDRV_StrokeAndFillPath( PHYSDEV dev ) DECLSPEC_HIDDEN;
 extern BOOL PSDRV_StrokePath( PHYSDEV dev ) DECLSPEC_HIDDEN;
 
-extern void PSDRV_MergeDevmodes(PSDRV_DEVMODE *dm1, PSDRV_DEVMODE *dm2,
+extern void PSDRV_MergeDevmodes(PSDRV_DEVMODE *dm1, const PSDRV_DEVMODE *dm2,
 			 PRINTERINFO *pi) DECLSPEC_HIDDEN;
 extern BOOL PSDRV_GetFontMetrics(void) DECLSPEC_HIDDEN;
 extern PPD *PSDRV_ParsePPD(char *fname, HANDLE printer) DECLSPEC_HIDDEN;