1 files changed, 9 insertions, 14 deletions

diff --git a/sys/dev/tpm/tpm_tis.c b/sys/dev/tpm/tpm_tis.c
index 93f1ae3f7b387..170fdd3967fff 100644
--- a/sys/dev/tpm/tpm_tis.c
+++ b/sys/dev/tpm/tpm_tis.c
@@ -100,26 +100,21 @@ char *tpmtis_ids[] = {"MSFT0101", NULL};
 static int
 tpmtis_acpi_probe(device_t dev)
 {
-	struct resource *res;
-	int err, rid = 0;
-	uint32_t caps;
+	int err;
+	ACPI_TABLE_TPM23 *tbl;
+	ACPI_STATUS status;
 
 	err = ACPI_ID_PROBE(device_get_parent(dev), dev, tpmtis_ids, NULL);
 	if (err > 0)
 		return (err);
-
-	/* Check if device is in TPM 2.0 TIS mode */
-	res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
-	if (res == NULL)
-		return (ENXIO);
-
-	caps = bus_read_4(res, TPM_INTF_CAPS);
-	bus_release_resource(dev, SYS_RES_MEMORY, rid, res);
-	if ((caps & TPM_INTF_CAPS_VERSION) != TPM_INTF_CAPS_TPM20)
-		return (ENXIO);
+	/*Find TPM2 Header*/
+	status = AcpiGetTable(ACPI_SIG_TPM2, 1, (ACPI_TABLE_HEADER **) &tbl);
+	if(ACPI_FAILURE(status) ||
+	   tbl->StartMethod != TPM2_START_METHOD_TIS)
+	    err = ENXIO;
 
 	device_set_desc(dev, "Trusted Platform Module 2.0, FIFO mode");
-	return (BUS_PROBE_DEFAULT);
+	return (err);
 }
 
 static int