diff --git a/hw/xfree86/os-support/shared/vidmem.c b/hw/xfree86/os-support/shared/vidmem.c
index 514fc2fa7..68ed30e41 100644
--- a/hw/xfree86/os-support/shared/vidmem.c
+++ b/hw/xfree86/os-support/shared/vidmem.c
@@ -257,16 +257,3 @@ xf86LinearVidMem(void)
     xf86InitVidMem();
     return vidMemInfo.linearSupported;
 }
-
-void
-xf86MapReadSideEffects(int ScreenNum, int Flags, pointer base,
-                       unsigned long Size)
-{
-    if (!(Flags & VIDMEM_READSIDEEFFECT))
-        return;
-
-    if (!vidMemInfo.initialised || !vidMemInfo.readSideEffects)
-        return;
-
-    vidMemInfo.readSideEffects(ScreenNum, base, Size);
-}
diff --git a/hw/xfree86/os-support/xf86OSpriv.h b/hw/xfree86/os-support/xf86OSpriv.h
index 65769c16f..bd734f554 100644
--- a/hw/xfree86/os-support/xf86OSpriv.h
+++ b/hw/xfree86/os-support/xf86OSpriv.h
@@ -38,7 +38,6 @@ typedef pointer (*SetWCProcPtr) (int, unsigned long, unsigned long, Bool,
                                  MessageType);
 typedef void (*ProtectMemProcPtr) (int, pointer, unsigned long, Bool);
 typedef void (*UndoWCProcPtr) (int, pointer);
-typedef void (*ReadSideEffectsProcPtr) (int, pointer, unsigned long);
 
 typedef struct {
     Bool initialised;
@@ -47,7 +46,6 @@ typedef struct {
     ProtectMemProcPtr protectMem;
     SetWCProcPtr setWC;
     UndoWCProcPtr undoWC;
-    ReadSideEffectsProcPtr readSideEffects;
     Bool linearSupported;
 } VidMemInfo, *VidMemInfoPtr;
 
diff --git a/hw/xfree86/os-support/xf86_OSproc.h b/hw/xfree86/os-support/xf86_OSproc.h
index 6be594651..106168aba 100644
--- a/hw/xfree86/os-support/xf86_OSproc.h
+++ b/hw/xfree86/os-support/xf86_OSproc.h
@@ -136,8 +136,6 @@ extern _X_EXPORT _X_DEPRECATED pointer xf86MapVidMem(int, int, unsigned long,
                                                      unsigned long);
 extern _X_EXPORT _X_DEPRECATED void xf86UnMapVidMem(int, pointer,
                                                     unsigned long);
-extern _X_EXPORT _X_DEPRECATED void xf86MapReadSideEffects(int, int, pointer,
-                                                           unsigned long);
 extern _X_EXPORT int xf86ReadBIOS(unsigned long, unsigned long, unsigned char *,
                                   int);
 extern _X_EXPORT Bool xf86EnableIO(void);