Bluetooth: Add BT_POWER L2CAP socket option.

Add BT_POWER socket option used to control the power
characteristics of the underlying ACL link. When the remote end
has put the link in sniff mode and the host stack wants to send
data we need need to explicitly exit sniff mode to work well with
certain devices (For example, A2DP on Plantronics Voyager 855).
However, this causes problems with HID devices.

Hence, moving into active mode when sending data, irrespective
of who set the sniff mode has been made as a socket option. By
default, we will move into active mode. HID devices can set the
L2CAP socket option to prevent this from happening.

Currently, this has been implemented for L2CAP sockets. This has been
tested with incoming and outgoing L2CAP sockets for HID and A2DP.

Based on discussions on linux-bluetooth and patches submitted by
Andrei Emeltchenko.

Signed-off-by: Jaikumar Ganesh <jaikumar@google.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

1 files changed, 6 insertions, 3 deletions

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index ce67d0ff486f..0408a93570d6 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -507,7 +507,7 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
         if (acl->state == BT_CONNECTED &&
                         (sco->state == BT_OPEN || sco->state == BT_CLOSED)) {
                 acl->power_save = 1;
-                hci_conn_enter_active_mode(acl);
+                hci_conn_enter_active_mode(acl, BT_POWER_FORCE_ACTIVE_ON);
 
                 if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
                         /* defer SCO setup until mode change completed */
@@ -688,7 +688,7 @@ int hci_conn_switch_role(struct hci_conn *conn, __u8 role)
 EXPORT_SYMBOL(hci_conn_switch_role);
 
 /* Enter active mode */
-void hci_conn_enter_active_mode(struct hci_conn *conn)
+void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active)
 {
         struct hci_dev *hdev = conn->hdev;
 
@@ -697,7 +697,10 @@ void hci_conn_enter_active_mode(struct hci_conn *conn)
         if (test_bit(HCI_RAW, &hdev->flags))
                 return;
 
-        if (conn->mode != HCI_CM_SNIFF || !conn->power_save)
+        if (conn->mode != HCI_CM_SNIFF)
+                goto timer;
+
+        if (!conn->power_save && !force_active)
                 goto timer;
 
         if (!test_and_set_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend)) {