diff --git a/dlls/winex11.drv/dib.c b/dlls/winex11.drv/dib.c
index 2021aabd2ae..ed65af35170 100644
--- a/dlls/winex11.drv/dib.c
+++ b/dlls/winex11.drv/dib.c
@@ -4049,7 +4049,8 @@ INT CDECL X11DRV_SetDIBits( X11DRV_PDEVICE *physDev, HBITMAP hbitmap, UINT start
   {
       unsigned int srcwidthb = ds.dsBm.bmWidthBytes;
       int dstwidthb = X11DRV_DIB_GetDIBWidthBytes( width, descr.infoBpp );
-      LPBYTE dbits = physBitmap->base, sbits = (LPBYTE)bits + (startscan * srcwidthb);
+      LPBYTE dbits = physBitmap->base;
+      const BYTE *sbits = (const BYTE*)bits + (startscan * srcwidthb);
       int widthb;
       UINT y;
 
diff --git a/dlls/winex11.drv/ime.c b/dlls/winex11.drv/ime.c
index f9e0538ca4e..2fcd285755d 100644
--- a/dlls/winex11.drv/ime.c
+++ b/dlls/winex11.drv/ime.c
@@ -189,7 +189,7 @@ static int updateField(DWORD origLen, DWORD origOffset, DWORD currentOffset,
      return currentOffset;
 }
 
-static HIMCC updateCompStr(HIMCC old, LPWSTR compstr, DWORD len)
+static HIMCC updateCompStr(HIMCC old, LPCWSTR compstr, DWORD len)
 {
     /* we need to make sure the CompStr, CompClaus and CompAttr fields are all
      * set and correct */
@@ -923,7 +923,7 @@ BOOL WINAPI ImeSetCompositionString(HIMC hIMC, DWORD dwIndex, LPCVOID lpComp,
 
         if (dwCompLen && lpComp)
         {
-            newCompStr = updateCompStr(lpIMC->hCompStr, (LPWSTR)lpComp, dwCompLen / sizeof(WCHAR));
+            newCompStr = updateCompStr(lpIMC->hCompStr, (LPCWSTR)lpComp, dwCompLen / sizeof(WCHAR));
             ImmDestroyIMCC(lpIMC->hCompStr);
             lpIMC->hCompStr = newCompStr;
 
diff --git a/dlls/winex11.drv/settings.c b/dlls/winex11.drv/settings.c
index e2aafbceae1..7f0753a4301 100644
--- a/dlls/winex11.drv/settings.c
+++ b/dlls/winex11.drv/settings.c
@@ -243,7 +243,7 @@ static BOOL write_registry_settings(const DEVMODEW *dm)
         return FALSE;
 
 #define set_value(name, data) \
-    if (RegSetValueExA(hkey, name, 0, REG_DWORD, (LPBYTE)(data), sizeof(DWORD))) \
+    if (RegSetValueExA(hkey, name, 0, REG_DWORD, (const BYTE*)(data), sizeof(DWORD))) \
         ret = FALSE
 
     set_value("DefaultSettings.BitsPerPel", &dm->dmBitsPerPel);