[Rxtx] loopback puzzle

[Trent Jarvi]

Hi Stephen

The kernel probably already does everything needed.  Eventually, we will 
be receiving those events and sending events to applications that a device 
was plugged in. Depending upon the OS, either the kernel events are not 
detectable or rxtx ignores them at this time.

Right now the commports are enumerated when RXTXCommDriver's static 
initialize is called.  Thats usually the first 
'CommPortIdentifier.getPortIdentifiers();' thats called. This is in 
RXTXCommDriver.java.  A small enhancement that many folks would like would 
be to allow rescanning of ports.  Restarting the application after 
changing hardware is the usual path.  Also consider that we do not 
currently make special efforts to deal with hardware vanishing.

Whatever error you see after hardware is removed was not thought of as a 
flow control path for UARTs being ripped off the motherboard.  It just 
wasn't something that happened.

On Mon, 11 Sep 2006, Dr. Stephen Judd wrote:

> AH!  great.
> So my mental model was reasonable, but ahead of its time.
> Now how do I adjust my mental image? Does rebooting the machine
> change anything? How do I get to those new ports?!
> sj
>
> On 2006 Sep 11, at 7:00 PM, Trent Jarvi wrote:
>
>>
>> Hi Stephen
>>
>> The CommAPI 'specification' was written before ports could vanish and
>> appear.  There isn't a means of catching 'hotplug' events yet.  For
>> all
>> practical purposes, the hardware should not change while using CommAPI
>> 2.0.  This shortfall has been discussed as a possible addition to
>> future
>> 'standards' which rxtx will support.  For now, you have to adjust your
>> mental image :)
>>
>> On Mon, 11 Sep 2006, Dr. Stephen Judd wrote:
>>
>>> Many thanks to Dr. Lyon, Joachim Buechse, and Bob Jacobsen.
>>>
>>> Building on what I have learned from this group, my mental model has
>>> arrived at the point where I believe that the mere plugging in of
>>> a port
>>> expander (like the DUAL PORT USB to Serial RS-232 DB-9 Adapter Cable)
>>> will automagically change the list of ports available to
>>> CommPortIdentifier.getPortIdentifiers().
>>>
>>> Experiments say this is not true however. Using same SerialDemo as
>>> described below, the list does not change, even after plugging a
>>> live device
>>> into one of the resulting RS-232 ports, and restarting the app.
>>>
>>> What's broken now? my hardware? or still my head?
>>> sj
>>>
>>> On 2006 Sep 7, at 8:40 AM, Dr. Douglas Lyon wrote:
>
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