diff --git a/common/hw-gfx-gma-pch-vga.adb b/common/hw-gfx-gma-pch-vga.adb
index f090246..fd82740 100644
--- a/common/hw-gfx-gma-pch-vga.adb
+++ b/common/hw-gfx-gma-pch-vga.adb
@@ -29,13 +29,13 @@
    PCH_ADPA_VSYNC_ACTIVE_HIGH : constant := 1 * 2 **  4;
    PCH_ADPA_HSYNC_ACTIVE_HIGH : constant := 1 * 2 **  3;
 
-   PCH_ADPA_MASK : constant Word32 :=
-      PCH_TRANSCODER_SELECT_MASK or
+   function PCH_ADPA_MASK return Word32 is
+     (PCH_TRANSCODER_SELECT_MASK or
       PCH_ADPA_DAC_ENABLE        or
       PCH_ADPA_VSYNC_DISABLE     or
       PCH_ADPA_HSYNC_DISABLE     or
       PCH_ADPA_VSYNC_ACTIVE_HIGH or
-      PCH_ADPA_HSYNC_ACTIVE_HIGH;
+      PCH_ADPA_HSYNC_ACTIVE_HIGH);
 
    ----------------------------------------------------------------------------