I2C transactions errors

[strilov]

In certain configurations, I2C transactions fail. E.g. when on running in a VM on a laptop with a direct network connection to an FMC+Enclustra, or timing app monitoring software running on np04-srv-002 communication with PROD_MASTER_VDC (direct connection, no issue if connection is done through the control hub on np04-srv-012).

Issue suspected to be related "mid-level" I2C bus control over network and/or PC CPU.

[wesketchum]

Is this still an issue, @strilov? If so, is there any impact on ProtoDUNE-II (I suspect not if we stick to using np04-srv-012 ...)

[strilov]

Hi Wes. This issue is still outstanding, however it is not trivial to fix. It will require significant modifications to the timing firmware and software. The workaround is to run the timing partition with DUNEDAQ_OPMON_LEVEL set to 1 or lower, that way, information from ICs on the hardware will not be collected using I2C.