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linuxbluetoothbluez
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Reputation: 377

Bluez /Linux - connect: Device or resource busy on gatt_connect

Environment: C, Linux, Bluez 5.4

3rd gatt_connect gives an error. Seems there is some resource which is not closed or shutdown. No clue what.

Connect Device - gatt_connect
Disconnect Device - remove battery
Connect Device - gatt_connect
Disconnect Device - remove battery
Connect Device - gatt_connect

3rd Connect Device gives this error:

connect: Device or resource busy (16)
connect_cb connect error: Device or resource busy (16)

// Watcher called each time channel is disconnected.

static gboolean channel_watcher(GIOChannel *iochannel, GIOCondition cond, gpointer user_data)
{

        int devid = (int) user_data;
        g_io_channel_shutdown(iochannel, FALSE, NULL);
        g_io_channel_unref(iochannel);

        iochannel = NULL;
        return FALSE;
}

Makes the GATT connection:

GIOChannel* GattConnect(int dev_id, char *hwid, int handle, char *value)
{
        GIOChannel *chan;
        opt_listen=TRUE;
        opt_dst = hwid;
        opt_handle = handle;
        opt_value = value;

        chan = gatt_connect(opt_src, opt_dst, opt_dst_type, opt_sec_level, opt_psm, opt_mtu, connect_cb);

        if(chan == NULL) {
             fprintf(logFile, "GattConnect - null channel\n");
        }
        else {
           g_io_add_watch(chan, G_IO_HUP, channel_watcher, (void *)dev_id);
        }
       return chan;
}

Please provide ideas of what may may be causing the resource to be busy

Upvotes: 2

Views: 5763

Answers (1)

OlivierM
OlivierM

Reputation: 3212

Bluez accesses GATT services through a (Unix Domain) socket. If the connection fails then there is a timeout of 20 seconds before to timeout the socket.

I had a similar issue when I was implementing the example ble_scan in GattLib. To fix it I reduced the timeout on the send/receive of the socket:

    if (setsockopt (sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout)) < 0) {
        fprintf(stderr, "l2cap_connect: Failed to setsockopt for receive timeout.\n");
        return -1;
    }

    if (setsockopt (sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout)) < 0) {
        fprintf(stderr, "l2cap_connect: Failed to setsockopt for sending timeout.\n");
        return -1;
    }

I guess the GattLib ble_scan example does what you are trying to achieve: https://github.com/labapart/gattlib/blob/master/examples/ble_scan/ble_scan.c

Upvotes: 1

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