Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Wed, 19 Mar 2008 16:59:16 -0500

Folks,

Stephen wrote>

> Is there an asyn option that will cause I/O interrupt records to
process after a 
> connection problem? 

Right now there is no such option.  A few months ago I made a change to
asyn to add a status parameter to the asyn callback functions from a
driver to device support.  That would have made I/O Intr scanned records
change their severity to reflect the status.  However, on discussion
with developers I backed out of that modification, because it changed
the asyn API and would have required rewriting lots of drivers and
device support.

I am trying to come up with a backwards-compatible method to do this.
asyn has support for connection callbacks, but so far there has been
little or no device and driver support to take advantage of this.  We
need to start to use these tools, as more and more devices are on buses
that can disconnect and reconnect while the IOC is running.

However, your particular question is about stream device, which is using
the asynOctet interface in asyn.  The most commonly used asynOctet
drivers, drvAsynIPPort and drvAsynSerialPort do not actually support
callbacks, and hence do not support I/O Intr scanned records.  My
understanding is that stream device is using the "read with timeout" to
the asyn drivers, and then it is handling records that have I/O Intr
scanning.  So in your case it is really a question about stream device,
since it is device support and it thus should handle setting the
severity and status of the records if there is an asyn disconnect event.

Mark

> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Schuh, Stephen
> Sent: Tuesday, March 18, 2008 2:27 PM
> To: [email protected]
> Subject: Severity of I/O interrupt records
> 
> I am using streamdevice to communicate with a VME crate 
> controller.  One record sends a query string to the crate and 
> receives a string as a reply.  The reply string contains a 
> lot of information and needs to be mapped to several records. 
>  The records that receive this information are all 
> streamdevice records with I/O interrupt processing.  This all works.
> 
> My problem is that I want the severity of all the I/O 
> interrupt records to be set to invalid if there is a problem 
> with the communication to the crate.  The record that sends 
> the query string has invalid severity in this case.  Can 
> anyone suggest a nice way to propagate that invalid severity 
> to all the I/O interrupt records?  I thought about disabling 
> the records, but I think I would need to process the records 
> to make this work, and I don't know how to cause I/O 
> interrupt records to process.  Is there an asyn option that 
> will cause I/O interrupt records to process after a 
> connection problem?
> 
> thank you,
> Stephen
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System