Problem with streamDevice and I/O Intr

[Florian Feldbauer <florian@ep1.ruhr-uni-bochum.de>]

Hello all,

I ran into a problem when reading from a serial device using I/O Intr
processing with streamDevice. I receive 64 messages in series and have
one record for each message.
Now and then  I get the error message from epics:

timerQueue INTERNAL ERROR (PANDA:FEMC:PROTO192:THMP:680:CHK:00): 
timerExpired() unexpected ioAction None

Any idea how to fix this problem?

This is the db:
record (scalcout, "THMP:$(ID):CHK:$(no)")
{
  field (DTYP, "stream")
  field (SCAN, "I/O Intr")
  field (CALC, "((K XOR L) XOR C)==E?(K<<8)+L:LL")
  field (OUT,  "@THMP.proto getMsg($(no)) USBCAN1")
  field (INPC, "$(no)")
  field (INLL, "INV CHK")
}

This is the protocol:
Terminator = CR;
getMsg{
  in "t6804\${2}%(K)2X%(L)2X%(E)2X";
}

This is an example string, which is sent from the device:
t68043F34AAA1\r

Best regards
Florian