diff --git a/sys/dev/ath/if_ath_pci.c b/sys/dev/ath/if_ath_pci.c
index 686fc4daa71..d11f9293287 100644
--- a/sys/dev/ath/if_ath_pci.c
+++ b/sys/dev/ath/if_ath_pci.c
@@ -148,8 +148,8 @@ ath_pci_attach(device_t dev)
 		device_printf(dev, "cannot map register space\n");
 		goto bad;
 	}
-	/* NB: these casts are known to be safe */
-	sc->sc_st = (HAL_BUS_TAG) rman_get_bustag(psc->sc_sr);
+	/* XXX uintptr_t is a bandaid for ia64; to be fixed */
+	sc->sc_st = (HAL_BUS_TAG)(uintptr_t) rman_get_bustag(psc->sc_sr);
 	sc->sc_sh = (HAL_BUS_HANDLE) rman_get_bushandle(psc->sc_sr);
 	/*
 	 * Mark device invalid so any interrupts (shared or otherwise)