2014-02-18 18:55:06

by Petri Gynther

Subject: [PATCHv2] adapter: Handle MGMT_SETTING_LE change

On dual-mode Bluetooth adapters, BLE is not enabled by default. When bluetoothd
starts, BLE is enabled in read_info_complete(), but this management action does
not always complete before adapter_start() is called. Therefore, bluetoothd
needs to handle the MGMT_SETTING_LE change correctly in settings_changed().
Specifically, trigger_passive_scanning() needs to be called so that paired BLE
devices (e.g. HoG devices) are able to reconnect back to host.

The trace below shows this case:
bluetoothd[1087]: src/adapter.c:adapter_start() adapter /org/bluez/hci0 has been enabled
=> adapter_start() is called, but BLE is not yet enabled
bluetoothd[1087]: src/adapter.c:load_link_keys_complete() link keys loaded for hci0
bluetoothd[1087]: src/adapter.c:load_ltks_complete() LTKs loaded for hci0
bluetoothd[1087]: src/adapter.c:get_connections_complete() Connection count: 0
bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000000c1
bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000040
bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002c1
bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000200
=> BLE got enabled, so need to call trigger_passive_scanning()
bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002d1
bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000010
bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002d3
bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000002

The issue is easily reproducible with this init sequence:
hciconfig hci0 up
bluetoothd -n -d
---
src/adapter.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/src/adapter.c b/src/adapter.c
index 08296bd..596e1eb 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -405,6 +405,7 @@ static void store_adapter_info(struct btd_adapter *adapter)
static void trigger_pairable_timeout(struct btd_adapter *adapter);
static void adapter_start(struct btd_adapter *adapter);
static void adapter_stop(struct btd_adapter *adapter);
+static void trigger_passive_scanning(struct btd_adapter *adapter);

static void settings_changed(struct btd_adapter *adapter, uint32_t settings)
{
@@ -434,6 +435,12 @@ static void settings_changed(struct btd_adapter *adapter, uint32_t settings)
}
}

+ if (changed_mask & MGMT_SETTING_LE) {
+ if ((adapter->current_settings & MGMT_SETTING_POWERED) &&
+ (adapter->current_settings & MGMT_SETTING_LE))
+ trigger_passive_scanning(adapter);
+ }
+
if (changed_mask & MGMT_SETTING_CONNECTABLE)
g_dbus_emit_property_changed(dbus_conn, adapter->path,
ADAPTER_INTERFACE, "Connectable");
--
1.9.0.rc1.175.g0b1dcb5

2014-02-18 19:49:54

by Johan Hedberg

Subject: Re: [PATCHv2] adapter: Handle MGMT_SETTING_LE change

Hi Petri,

On Tue, Feb 18, 2014, Petri Gynther wrote:
> On dual-mode Bluetooth adapters, BLE is not enabled by default. When bluetoothd
> starts, BLE is enabled in read_info_complete(), but this management action does
> not always complete before adapter_start() is called. Therefore, bluetoothd
> needs to handle the MGMT_SETTING_LE change correctly in settings_changed().
> Specifically, trigger_passive_scanning() needs to be called so that paired BLE
> devices (e.g. HoG devices) are able to reconnect back to host.
>
> The trace below shows this case:
> bluetoothd[1087]: src/adapter.c:adapter_start() adapter /org/bluez/hci0 has been enabled
> => adapter_start() is called, but BLE is not yet enabled
> bluetoothd[1087]: src/adapter.c:load_link_keys_complete() link keys loaded for hci0
> bluetoothd[1087]: src/adapter.c:load_ltks_complete() LTKs loaded for hci0
> bluetoothd[1087]: src/adapter.c:get_connections_complete() Connection count: 0
> bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000000c1
> bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000040
> bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002c1
> bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000200
> => BLE got enabled, so need to call trigger_passive_scanning()
> bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002d1
> bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000010
> bluetoothd[1087]: src/adapter.c:new_settings_callback() Settings: 0x000002d3
> bluetoothd[1087]: src/adapter.c:settings_changed() Changed settings: 0x00000002
>
> The issue is easily reproducible with this init sequence:
> hciconfig hci0 up
> bluetoothd -n -d
> ---
> src/adapter.c | 7 +++++++
> 1 file changed, 7 insertions(+)

Applied (after reformatting the commit message a bit to follow the "less
than 76 chars wide" rule). Thanks.

Johan