Linux 6.13 To Drop Fieldbus Just Five Years After Being Merged

Merged back in 2019 was the Fieldbus subsystem as a set of network protocols for real-time distributed control of automated industrial systems. But now five years later, Fieldbus is being removed from the mainline Linux kernel since the code hasn't been maintained.

Fieldbus is used for connecting different systems/components/instruments within industrial environments. As written about last month, Fieldbus is at risk for removal since no developers have been actively maintaining the code and it's not clear how much actual use this code within the mainline Linux kernel is seeing among industrial systems. With no one stepping up in the past few weeks to volunteer to maintain the code or otherwise any stakeholders saying they are still using this and running their industrial machines on mainline kernels, the code has hit the chopping block.

The patch by Philipp Hortmann to remove the 3k lines of code for Fieldbus has been queued into staging-next and thus set to be removed for the upcoming Linux 6.13 merge window. Hortmann explains in the removal patch:

"Sven Van Asbroeck contributed this driver in 2019.

The following reasons lead to the removal:
- This driver generates maintenance workload
- only 11 patches during the last 3 years. Part of the patches seem to be motivated because of maintenance (for example - remove deprecated function)
- Maintainer lost interest, last "Reviewed-by:" is May 2021
- no blog about usage of this driver

The staging subsystem is the way for drivers into the kernel - at current speed and interest this is never going to happen. I think that fieldbus is an interesting topic. But when almost nobody cares about this driver, it does not make sense to keep it. Please consider that support will remain for years in the longterm kernels."

So barring any last minute changes, Fieldbus will be bid farewell with the upcoming Linux 6.13 kernel now that Greg Kroah-Hartman has picked up this patch in the staging-next Git branch.