Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Thu, 30 Mar 2006 17:37:54 -0600

Folks,

This is a follow-up to the earlier discussion today about the behavior
of medm with the scaler record.

Pressing the Count button would result in both the Count and Done states
being selected.  Tim Mooney found and fixed bug in the scaler record
that was causing the monitor on the CNT field to be posted twice when
starting the scaler.  However, this was not the problem causing the medm
widget to misbehave, because that continues even after fixing the scaler
record.

I think the medm problem is definitely with some shareable library which
is used at run-time by the medm client on Linux.

Here is the test setup I used:

- X server is running on Windows, Exceed 7.1.0.0 in all cases.

- Runing the same medm binary (medm 3.0.0, EPICS 3.13.7) on two Linux
systems.

On the older Linux system the scaler CNT widget behaves badly, as
described previously.  This version is:

corvette> more /proc/version 
Linux version 2.4.20-20.9smp ([email protected]) (gcc
version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #1 SMP Mon Aug 18
11:32:15 EDT 2003 

On a newer Linux system the scaler CNT widget behaves fine.  This
version is:

vincent> more /proc/version 
Linux version 2.6.9-22.0.1.EL ([email protected]) (gcc version 3.4.3
20050227 (Red Hat 3.4.3-22.1)) #1 Thu Oct 27 10:38:16 CDT 2005

Since I am running exactly the same medm binary on exactly the same X
server, the only difference is the run-time libraries that are present
on the Linux system that is running medm.  There must be a problem with
the X libraries on the old Redhat 2.4.20 system.  I conclude that there
is no problem with the scaler record or with medm.

Mark

> -----Original Message-----
> From: Mark Rivers 
> Sent: Thursday, March 30, 2006 4:55 PM
> To: 'Tim Mooney'
> Cc: 'Kenneth Evans, Jr.'; 'Jeff Hill'; 'Dirk Zimoch'; 
> 'Leicester, PJ (Pete)'; 'Ralph Lange (BESSY)'; 'Ned Arnold'; 
> 'Andrew Johnson'
> Subject: scaler record medm problems
> 
> Folks,
> 
> I have applied this fix to the scaler record.  I used 
> camonitor on the CNT field, and indeed it fixes the problem 
> of two monitors being posted for CNT=Count when acquisition starts.
> 
> However it does NOT fix the problem with medm on Linux.  medm 
> running on Windows continues to work fine, medm running on 
> Linux (but displaying on Windows or Linux) does not work. The 
> Count/Done choice button gets into a weird state with both 
> states selected, not sending events, etc.
> 
> So the question is why is that particular choice button messing up?
> 
> - It does not have to do with 2 monitors being posted quickly 
> on the PV it controls.
> - It should not have to do with the caPutCallback behavior of 
> the scaler record, because medm does not use caPutCallback, right?
> 
> Any ideas what to look for next?
> 
> Mark
> 
> 
> > -----Original Message-----
> > From: Tim Mooney [mailto:[email protected]] 
> > Sent: Thursday, March 30, 2006 2:14 PM
> > To: Mark Rivers
> > Cc: Tim Mooney; Kenneth Evans, Jr.; Jeff Hill; Dirk Zimoch; 
> > Leicester, PJ (Pete); Ralph Lange (BESSY); Ned Arnold; 
> Andrew Johnson
> > Subject: Re: gateway enum writes
> > 
> > Tim Mooney wrote:
> > 
> >  > There's an error in the scaler software.  It should not be 
> > posting CNT
> >  > unless it changed CNT.  This will take some time to fix 
> > thoroughly, but
> >  > at least the record should never post CNT = 0 ("Done"), 
> > because it never
> >  > sets CNT to this value.  I've committed this fix to cvs. 
>  The other
> >  > transition will take some thought, because 1->0 can come 
> > from the user
> >  > and from device support, and these can race.
> > 
> > Oops.  This hasn't been true for a long time.  I *can* post 
> > at the time of
> > change, and I actually committed that bug fix.  Here are 
> the changes:
> > 
> > static long process(pscal)
> > 	...
> > 	/* If we're being called as a result of a done-counting 
> > interrupt, */
> > 	/* (*pdset->done)(card) will return TRUE */
> > 	if ((*pdset->done)(card)) {
> > 		pscal->ss = SCALER_STATE_IDLE;
> > 		/* Auto-count cycle is not allowed to reset 
> > .CNT field. */
> > 		if (pscal->us == USER_STATE_COUNTING) {
> > 			pscal->cnt = 0;
> > +			db_post_events(pscal,&(pscal->cnt),DBE_VALUE);
> > 			pscal->us = USER_STATE_IDLE;
> > 			justFinishedUserCount = 1;
> > 			if (pscal->ppn) putNotifyOperation = 1;
> > 		}
> > 	}
> > 	...
> > 		if (handled) {
> > 			pscal->pcnt = pscal->cnt;
> > -			Debug(2) "process: posting .CNT field 
> > (%d)\n", pscal->cnt);}
> > -			db_post_events(pscal,&(pscal->cnt),DBE_VALUE);
> > 		}
> > 	}
> > 
> > 
> > 
> > -- 
> > Tim Mooney ([email protected]) (630)252-5417
> > Beamline Controls & Data Acquisition Group
> > Advanced Photon Source, Argonne National Lab
> > 
> > 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System