Permission denied when opening serialport

[Ivan1120]

Hi guys:
Why I always get "Permission denied", when my program is opening serial port?? How to enable the permission?? I tried to key chmod 777 /dev/ttyUSB0, but it was not working.

[SGaist]

What are the exact permission on that device ?

[Ivan1120]

I am not sure, because i use errorString() function in the QSerialPort and it shows permission denied.

[SGaist]

What does a ls -la return ?

[kuzulis]

In this case, a reason maybe is in that need to delete a lock file (of course if a lock file exists)...