This is presented as a raw property rather than a parsed "PathLoss"
property because in the case of many devices, this specific field will
not be present and instead the TX power will have to be parsed from
manufacturer-specific data anyway.
It's better therefore to document the Path Loss equation rather than
hide it.
---
doc/device-api.txt | 12 ++++++++++++
src/adapter.c | 6 ++++--
src/device.c | 41 +++++++++++++++++++++++++++++++++++++++++
src/device.h | 1 +
4 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/doc/device-api.txt b/doc/device-api.txt
index 86d8af8..68388e9 100644
--- a/doc/device-api.txt
+++ b/doc/device-api.txt
@@ -193,3 +193,15 @@ Properties string Address [readonly]
Received Signal Strength Indicator of the remote
device (inquiry or advertising).
+
+ int16 TxPower [readonly, optional]
+
+ Transmission power claimed by the remote device
+ (inquiry or advertising). Many devices may not make
+ this available at all, or may incorporate this data
+ into a manufacturer or service-specific field instead.
+
+ However the remote transmission power is obtained,
+ path loss can be calculated by the equation:
+
+ Path Loss = Tx Power - RSSI
diff --git a/src/adapter.c b/src/adapter.c
index 92ee1a0..1b44dc5 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -1585,16 +1585,17 @@ static int compare_sender(gconstpointer a, gconstpointer b)
return g_strcmp0(client->owner, sender);
}
-static void invalidate_rssi(gpointer a)
+static void invalidate_inquiry_data(gpointer a)
{
struct btd_device *dev = a;
device_set_rssi(dev, 0);
+ device_set_tx_power(dev, 127);
}
static void discovery_cleanup(struct btd_adapter *adapter)
{
- g_slist_free_full(adapter->discovery_found, invalidate_rssi);
+ g_slist_free_full(adapter->discovery_found, invalidate_inquiry_data);
adapter->discovery_found = NULL;
}
@@ -4715,6 +4716,7 @@ static void update_found_devices(struct btd_adapter *adapter,
device_set_legacy(dev, legacy);
device_set_rssi(dev, rssi);
+ device_set_tx_power(dev, eir_data.tx_power);
if (eir_data.appearance != 0)
device_set_appearance(dev, eir_data.appearance);
diff --git a/src/device.c b/src/device.c
index 875a5c5..d4ebf4f 100644
--- a/src/device.c
+++ b/src/device.c
@@ -219,6 +219,7 @@ struct btd_device {
bool legacy;
int8_t rssi;
+ int8_t tx_power;
GIOChannel *att_io;
guint cleanup_id;
@@ -812,6 +813,28 @@ static gboolean dev_property_exists_rssi(const GDBusPropertyTable *property,
return TRUE;
}
+static gboolean dev_property_get_tx_power(const GDBusPropertyTable *property,
+ DBusMessageIter *iter, void *data)
+{
+ struct btd_device *dev = data;
+ dbus_int16_t val = dev->tx_power;
+
+ dbus_message_iter_append_basic(iter, DBUS_TYPE_INT16, &val);
+
+ return TRUE;
+}
+
+static gboolean dev_property_exists_tx_power(const GDBusPropertyTable *property,
+ void *data)
+{
+ struct btd_device *dev = data;
+
+ if (dev->tx_power == 127)
+ return FALSE;
+
+ return TRUE;
+}
+
static gboolean dev_property_get_trusted(const GDBusPropertyTable *property,
DBusMessageIter *iter, void *data)
{
@@ -1957,6 +1980,8 @@ static const GDBusPropertyTable device_properties[] = {
{ "Blocked", "b", dev_property_get_blocked, dev_property_set_blocked },
{ "LegacyPairing", "b", dev_property_get_legacy },
{ "RSSI", "n", dev_property_get_rssi, NULL, dev_property_exists_rssi },
+ { "TxPower", "n", dev_property_get_tx_power, NULL,
+ dev_property_exists_tx_power },
{ "Connected", "b", dev_property_get_connected },
{ "UUIDs", "as", dev_property_get_uuids },
{ "Modalias", "s", dev_property_get_modalias, NULL,
@@ -4107,6 +4132,22 @@ void device_set_rssi(struct btd_device *device, int8_t rssi)
DEVICE_INTERFACE, "RSSI");
}
+void device_set_tx_power(struct btd_device *device, int8_t tx_power)
+{
+ if (!device)
+ return;
+
+ if (device->tx_power == tx_power)
+ return;
+
+ DBG("tx_power %d", tx_power);
+
+ device->tx_power = tx_power;
+
+ g_dbus_emit_property_changed(dbus_conn, device->path,
+ DEVICE_INTERFACE, "TxPower");
+}
+
static gboolean start_discovery(gpointer user_data)
{
struct btd_device *device = user_data;
diff --git a/src/device.h b/src/device.h
index 2e0473e..b568593 100644
--- a/src/device.h
+++ b/src/device.h
@@ -88,6 +88,7 @@ void btd_device_set_trusted(struct btd_device *device, gboolean trusted);
void device_set_bonded(struct btd_device *device, uint8_t bdaddr_type);
void device_set_legacy(struct btd_device *device, bool legacy);
void device_set_rssi(struct btd_device *device, int8_t rssi);
+void device_set_tx_power(struct btd_device *device, int8_t tx_power);
bool btd_device_is_connected(struct btd_device *dev);
uint8_t btd_device_get_bdaddr_type(struct btd_device *dev);
bool device_is_retrying(struct btd_device *device);
--
2.1.0.rc2.206.gedb03e5
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