diff --git a/sys/dev/agp/agp_amd64.c b/sys/dev/agp/agp_amd64.c
index 3d19e640..669bfa0d 100644
--- a/sys/dev/agp/agp_amd64.c
+++ b/sys/dev/agp/agp_amd64.c
@@ -459,7 +459,7 @@ agp_amd64_via_init(device_t dev)
 	agp_amd64_apbase_fixup(dev);
 	pci_cfgregwrite(0, 1, 0, AGP3_VIA_ATTBASE, sc->gatt->ag_physical, 4);
 	pci_cfgregwrite(0, 1, 0, AGP3_VIA_GARTCTRL,
-	    pci_cfgregread(0, 1, 0, AGP3_VIA_ATTBASE, 4) | 0x180, 4);
+	    pci_cfgregread(0, 1, 0, AGP3_VIA_GARTCTRL, 4) | 0x180, 4);
 }
 
 static int