Return "Resource temporarily unavailable" when using Qt bluetooth function

[Mihan]

Hi 

I'm using Qt Bluetooth to connect some peripheral devices. But the "QLowEnergyController" ready to "connectToDevice()", the system output is :

   qt.bluetooth.bluez: void QBluetoothSocketPrivate::_q_readNotify() 76 error: -1 "Resource temporarily unavailable"

I don't know what resource is unavailable. Here is the output of "ulimit -a":

core file size          (blocks, -c) unlimited data seg size           (kbytes, -d) unlimited scheduling priority             (-e) 0file size               (blocks, -f) unlimited pending signals                 (-i) 1379max locked memory       (kbytes, -l) 64max memory size         (kbytes, -m) unlimitedopen files                      (-n) 1024pipe size            (512 bytes, -p) 8POSIX message queues     (bytes, -q) 819200real-time priority              (-r) 0stack size              (kbytes, -s) 8192cpu time               (seconds, -t) unlimited max user processes              (-u) 1379virtual memory          (kbytes, -v) unlimited file locks                      (-x) unlimited

How can I fix this.

[b36401]

In addition please note that "resource temporarily unavailable" message may mean some exact resource the process tries to access (not allocate as supposed with ulimit counters.

[karangajjar]

Hi 铭恒 李 ,

This issue seems to be specific to Qt and not NXP. So it would be better if you post your question on Qt support However, we found some links below which might be useful:

[QTBUG-58240] Bluetooth module fails to get services from devices - Qt Bug Tracker 

[QTBUG-51820] QLowEnergyController::connected never gets emitted - Qt Bug Tracker 

Regards,

Karan Gajjar

[Mihan]

Thanks karan.gajjar@volansystech.com‌

I think It can not control some normal devices like mouse and keyboard (instead of the system)

OTOH,What about this error:

         qt.bluetooth.bluez: void QBluetoothSocketPrivate::_q_readNotify() 81 error: -1 "Connection timed out"

I think the Bluez need to be sent something like heart-beat packet to keep the connection on. Is that right?

What should the devices send to bluez?