Hi Andre,
> This patch implements a fixup required by auto connection mechanism
> in order to work properly after a power on.
>
> When hdev is closed (e.g. Mgmt power off command, RFKILL or controller
> is reset), the ongoing active connections are silently dropped by the
> controller (no Disconnection Complete Event is sent to host). For that
> reason, the devices that require HCI_AUTO_CONN_ALWAYS are not added to
> hdev->pending_auto_conn list and they won't auto connect. So to fix
> this issue, after adapter is powered on, we should add all HCI_AUTO_
> CONN_ALWAYS address to hdev->pending_auto_conn list. Besides that, we
> always have to check if there are pending auto connections and start
> the background scanning if it is the case.
>
> This way, the auto connection mechanism works propely after a power
> off and power on sequence as well as RFKILL block/unblock.
>
> Signed-off-by: Andre Guedes <andre.guedes@xxxxxxxxxxxxx>
> ---
> include/net/bluetooth/hci_core.h | 2 ++
> net/bluetooth/hci_core.c | 49 ++++++++++++++++++++++++++++++++++++++++
> net/bluetooth/mgmt.c | 2 ++
> 3 files changed, 53 insertions(+)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index 322918f..379bb36 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -786,6 +786,8 @@ bool hci_is_scan_and_conn_supported(struct hci_dev *hdev);
>
> void hci_check_background_scan(struct hci_dev *hdev);
>
> +void __hci_fixup_auto_conn(struct hci_dev *hdev);
> +
> int hci_uuids_clear(struct hci_dev *hdev);
>
> int hci_link_keys_clear(struct hci_dev *hdev);
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 44d3f99..63a56f5 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -3090,6 +3090,55 @@ void hci_check_background_scan(struct hci_dev *hdev)
> BT_ERR("Failed to start background scanning: err %d", err);
> }
>
> +/* This functions implements a fixup required by auto connection mechanism
> + * in order to work properly after a power on.
> + *
> + * When hdev is closed (e.g. Mgmt power off command, RFKILL or controller is
> + * reset), the ongoing active connections are silently dropped by the
> + * by the controller (no Disconnection Complete Event is sent to host). For
> + * that reason, the devices that require HCI_AUTO_CONN_ALWAYS are not add to
> + * hdev->pending_auto_conn list and they won't auto connect. So to fix this
> + * issue, after adapter is powered on, we should add all HCI_AUTO_CONN_ALWAYS
> + * address to hdev->pending_auto_conn list. Besides that, we always have to
> + * check if there are pending auto connections and start the background
> + * scanning if it is the case.
> + *
> + * This function requires the caller holds hdev->lock.
> + */
> +void __hci_fixup_auto_conn(struct hci_dev *hdev)
I have no idea why you call this a fixup function. For me this is normal procedure. On power down we should clear the list of pending connections and on power up we re-establish it.
> +{
> + struct hci_conn_params *p;
> + struct bdaddr_list *entry;
> +
> + list_for_each_entry(p, &hdev->conn_params, list) {
> + if (p->auto_connect != HCI_AUTO_CONN_ALWAYS)
> + continue;
> +
> + entry = __find_pending_auto_conn(hdev, &p->addr, p->addr_type);
> + if (entry)
> + continue;
Why are we bothering here with checking if it exists. The list should be empty when we start.
> +
> + entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + BT_ERR("Out of memory of auto connection");
> + return;
> + }
> +
> + bacpy(&entry->bdaddr, &p->addr);
> + entry->bdaddr_type = p->addr_type;
> + list_add(&entry->list, &hdev->pending_auto_conn);
> + }
> +
> + if (!list_empty(&hdev->pending_auto_conn)) {
> + int err;
> +
> + err = start_background_scan(hdev);
> + if (err)
> + BT_ERR("Failed to start background scanning: err %d",
> + err);
Is it really worth to have the error here and not directly in start_background_scan.
> + }
> +}
> +
> static void inquiry_complete(struct hci_dev *hdev, u8 status)
> {
> if (status) {
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index 0e329e5..d396e47 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -4255,6 +4255,8 @@ static void powered_complete(struct hci_dev *hdev, u8 status)
>
> hci_dev_lock(hdev);
>
> + __hci_fixup_auto_conn(hdev);
> +
> mgmt_pending_foreach(MGMT_OP_SET_POWERED, hdev, settings_rsp, &match);
>
> new_settings(hdev, match.sk);
Regards
Marcel
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