Post Syndicated from corbet original https://lwn.net/Articles/955001/

The NVIDIA Mellanox ConnectX HW family of adapters is a complex beast,
supporting networking, InfiniBand, RDMA, and more. As a result, the mlx5
kernel driver that supports this hardware is also complex, as is the
interface that it provides to user space. The mlx5 developers have, for a
while now, been proposing
the addition of a new control interface, in the form of a separate virtual
device exported by the kernel, that would make vast amounts of debugging
information available. This driver has encountered some significant
opposition on its way toward the mainline, though, raising a number of
questions about appropriate interfaces and when subsystem maintainers have
veto power over submissions.