Experimental Physics and
Industrial Control System

"michael.abbott--- via Tech-talk" <[email protected]> · Mon, 16 Jul 2018 07:54:28 +0000

I have submitted bug #1781874 to launchpad to record this issue.

> -----Original Message-----
> From: Abbott, Michael (DLSLtd,RAL,TEC)
> Sent: 10 July 2018 10:36
> To: tech-talk ([email protected])
> Subject: RE: Failed caput not notified when using ca_array_put_callback
> 
> > Here is a very curious issue that I've just stumbled across:
> asynchronous
> > caput failure is reported, synchronous caput failure is hidden.
> 
> I have managed to pin this down a bit further by running wireshark with
> Michael Davidsaver's nice caproto plugin, and it appears that the IOC (not
> the client library) is responsible for hiding the synchronous caput
> failure.
> 
> Below is a transcript of two caput sessions.  In the first exchange we
> send CA_PROTO_WRITE and receive CA_PROTO_ERROR in response, in the second
> we send and receive CA_PROTO_WRITE_NOTIFY with ECA_NORMAL in the response.
> 
> This is tested with EPICS 3.14.12.3, so maybe this has been fixed in a
> more recent version, but given the cryptic character of this issue maybe
> not.
> 
> 
> Asynchronous
> 
> Client -> IOC
>     Command: Write (0x0004)
>     Payload Size: 8
>     DBR Type: DOUBLE (6)
>     Data Count: 1
>     Operation ID: 1
>     Server Channel ID: 519
>     Value: 0
> 
> IOC -> Client
>     Command: Error (0x000b)
>     Payload Size: 48
>     Data Type: 0x0000
>     Data Count: 0
>     Client Channel ID: 1
>     Status: ECA_PUTFAIL (0x000000a0)
>     Channel Access
>         Command: Write (0x0004)
>         Payload Size: 8
>         Data Type: 0x0006
>         Data Count: 1
>         Param 1: 0x00000207
>         Param 2: 0x00000001
>     Error Message: TS-DI-TMBF-02:MEM:CAPTURE_S
> 
> 
> Synchronous
> 
> Client -> IOC
>     Command: Write Notify (0x0013)
>     Payload Size: 8
>     DBR Type: DOUBLE (6)
>     Data Count: 1
>     Operation ID: 3
>     Server Channel ID: 520
>     Value: 0
> 
> IOC -> Client
>     Command: Write Notify (0x0013)
>     Payload Size: 0
>     DBR Type: DOUBLE (6)
>     Data Count: 1
>     Operation ID: 3
>     Status: ECA_NORMAL (0x00000001)

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System