diff --git a/common/ironlake/hw-gfx-gma-pch-hdmi.ads b/common/ironlake/hw-gfx-gma-pch-hdmi.ads
index 31d9564..1193711 100644
--- a/common/ironlake/hw-gfx-gma-pch-hdmi.ads
+++ b/common/ironlake/hw-gfx-gma-pch-hdmi.ads
@@ -14,12 +14,13 @@
 
 package HW.GFX.GMA.PCH.HDMI
 is
+   subtype IRL_PCH_HDMI_Port is PCH_HDMI_Port range PCH_HDMI_B .. PCH_HDMI_D;
 
    procedure On (Port_Cfg : Port_Config; FDI_Port : FDI_Port_Type)
    with
-      Pre => Port_Cfg.PCH_Port in PCH_HDMI_Port;
+      Pre => Port_Cfg.PCH_Port in IRL_PCH_HDMI_Port;
 
-   procedure Off (Port : PCH_HDMI_Port);
+   procedure Off (Port : IRL_PCH_HDMI_Port);
    procedure All_Off;
 
 end HW.GFX.GMA.PCH.HDMI;