Created attachment 370491 [details] [review]
proposed implementation

Hello,

We are working on reading terminals with brltty, so we'd like to make orca release the device so brltty can get its output shown and get keypresses.

This can be achieved by setting the enableBraille preference to False for e.g. the mate-terminal application, and conversely making brltty only read terminals, so each screen readers leaves the room for the other as expected.

The attached patch implements the missing bit: shutdown() was not actually reaching the global _brlAPI variable, it should call closeConnection() to really close the connection, and setting _brlAPI to None so that the memory can be freed by the python garbage collector.

Then, on braille refresh we can check for the enableBraille settings, and if disabled (we have just switched to a terminal), we shut brlapi down if it was still running.

Samuel