Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Tue, 6 Jan 2015 14:21:09 +0100

Hello Andrew,

I think now I understand what is going wrong here. It is a race condition.

In order to get unsolicited input, StreamDevice needs to poll asynDriver

frequently. If such a poll, which is a queued command issued by one of

the "I/O Intr" records, is still active when the asynchronous protocol

sends the reply (for the same record), StreamDevice tries to lock the

device for the out while the same asyUser (i.e. record) is still queued.

This is also consistent with your observation that a small delay works

around the problem.

I had not seen this before because I rarely ever used 'out' in an "I/O

Intr" record.

I will try to fix that. I have to make sure polling has finished before

handling the asynchronous protocol.

Dirk

On 05.01.2015 11:29, Dirk Zimoch wrote:

Hi Andrew,

This message does not ring a bell. StreamDevice does "lockRequest" at
the first 'out' command in a protocol. It unlocks the device at the end
of the protocol (or at error). The "I/O Intr" handlers for unsolicited
messages normally do not lock the device because they usually do not
have 'out' commands. But this seems to be different in your case, right?

Without the protocol it very hard to guess anything. And impossible to
test anything. If you do cannot send the real protocol, you may send a
"replacement" protocol in which you replace any command with a different
string.

Dirk

On 03.01.2015 00:31, Andrew Gomella wrote:

Hi Everyone,

I have a particularly tricky serial device I am working on programming.
To make matters worse it has a very slow response speed to commands.

It sends unsolicited commands, but also does normal request response
messages. I am usually polling the device every 4 seconds while it is
running. Very often when receiving the unsolicited commands I receive
the following error:

2014/12/30 20:14:13.939 timerQueue XR:Message lockRequest:
pasynManager->queueRequest() failed: asynManager::queueRequest is
already queued

I tried searching techtalk but cannot seem to find anyone with a similar
issue. This is very problematic because this device is very slow and the
unsolicited messages are the most important.  Also I should mention that
all commands I receive from the device need to be acknowledged, so
immediately after the "in" string in the protocol follow I have an out
string with the same format.

(Another problem I have is that if the device has messages to send very
close together in timing it will group them into a single message but
with an unpredictable order. I have no idea how to deal with this. I can
imagine a cascading mismatch sequence but this would be very complex. Is
regex the only other option? When it does group the messages they are
delimited by a space, but in all other instances it is just single
messages with no space. I almost need some sort of function to search
for a space and if it finds it to separate the messages, but otherwise
ignore the normal messages).

I'm using stream device 2-6 and asyn4-21. Unfortunately can't post the
db or protocol file because I had to sign a NDA for this device.

Thank you!
Andrew

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System