Hi Chan-Yeol,
> /*bluetooth kernel hci_conn.c */
> 382 void hci_conn_enter_active_mode(struct hci_conn *conn)
> 383 {
> 384 struct hci_dev *hdev = conn->hdev;
> 385
> 386 BT_DBG("conn %p mode %d", conn, conn->mode);
> 387
> 388 if (test_bit(HCI_RAW, &hdev->flags))
> 389 return;
> 390
> 391 if (conn->mode != HCI_CM_SNIFF || !conn->power_save)
> 392 goto timer;
> 393
> 394 if (!test_and_set_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend)) {
> 395 struct hci_cp_exit_sniff_mode cp;
> 396 cp.handle = __cpu_to_le16(conn->handle);
> 397 hci_send_cmd(hdev, OGF_LINK_POLICY,
> 398 OCF_EXIT_SNIFF_MODE, sizeof(cp), &cp);
> 399 }
> 400
> 401 timer:
> 402 if (hdev->idle_timeout > 0)
> 403 mod_timer(&conn->idle_timer,
> 404 jiffies + msecs_to_jiffies(hdev->idle_timeout));
> 405 }
> 406
>
> If possible, could you explain why this code checks !conn->power_save var.?
>
> Without this , if conn->mode==HCI_CM_SNIFF , we simply exit sniff
> mode,"OCF_EXIT_SNIFF_MODE".
>
> As far as I understood, whenever conn->mode is HCI_CM_SNIFF conn->power_save
> is 0.
> The reason is that hci_mode_change_evt() set conn->power_save as "0" when
> conn->mode !=HCI_CM_ACTIVE.
>
> Consequently we don't need to check that variable.
we do need that variable, because otherwise devices like HID which do
active sniff mode management fall over if we always try to exit sniff
mode only for a few bytes.
Regards
Marcel
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