On Sat, May 30, 2026 at 12:51 PM Luiz Angelo Daros de Luca
[off-list ref] wrote:

Explicitly enforce the presence of a CPU port (-EINVAL) and reject DSA
cascade links (-EOPNOTSUPP) during setup to prevent silent failures.

These topologies were already non-functional. Without a CPU port, the
driver does not activate CPU tagging. Additionally, the switch hardware
was not designed to be cascaded, and DSA links never worked because
CPU tagging is not enabled for them.

Signed-off-by: Luiz Angelo Daros de Luca <redacted>

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij