Bluetooth: Use proper invalid value for tx_power

The core specification defines 127 as the "not available" value (well,
"reserved" for BR/EDR and "not available" for LE - but essentially the
same). Therefore, instead of testing for 0 (which is in fact a valid
value) we should be using this invalid value to test if the tx_power is
available.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 6c414f4..344fea0 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -319,6 +319,9 @@
 #define HCI_FLOW_CTL_MODE_PACKET_BASED	0x00
 #define HCI_FLOW_CTL_MODE_BLOCK_BASED	0x01
 
+/* The core spec defines 127 as the "not available" value */
+#define HCI_TX_POWER_INVALID	127
+
 /* Extended Inquiry Response field types */
 #define EIR_FLAGS		0x01 /* flags */
 #define EIR_UUID16_SOME		0x02 /* 16-bit UUID, more available */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 515d0c3..9713a29 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1606,6 +1606,8 @@
 	hdev->esco_type = (ESCO_HV1);
 	hdev->link_mode = (HCI_LM_ACCEPT);
 	hdev->io_capability = 0x03; /* No Input No Output */
+	hdev->inq_tx_power = HCI_TX_POWER_INVALID;
+	hdev->adv_tx_power = HCI_TX_POWER_INVALID;
 
 	hdev->sniff_max_interval = 800;
 	hdev->sniff_min_interval = 80;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index c08ac7c..09c65712 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -202,6 +202,8 @@
 			     BIT(HCI_PERIODIC_INQ));
 
 	hdev->discovery.state = DISCOVERY_STOPPED;
+	hdev->inq_tx_power = HCI_TX_POWER_INVALID;
+	hdev->adv_tx_power = HCI_TX_POWER_INVALID;
 }
 
 static void hci_cc_write_local_name(struct hci_dev *hdev, struct sk_buff *skb)
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index a1a62ba..dedbb1d 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -484,7 +484,7 @@
 		ptr += (name_len + 2);
 	}
 
-	if (hdev->inq_tx_power) {
+	if (hdev->inq_tx_power != HCI_TX_POWER_INVALID) {
 		ptr[0] = 2;
 		ptr[1] = EIR_TX_POWER;
 		ptr[2] = (u8) hdev->inq_tx_power;