forked from unom/punktfunk
enricobuehler
77797a9e20
G8 of the gyro program, SDL-client half. The `Welcome` has always carried the backend the host actually RESOLVED, which is not necessarily the one the client asked for — Auto lands on Xbox 360 for anything not Sony/Valve/Xbox, and a Switch Pro on a Windows host folds to X360 too. No client read the field. So a player with an 8BitDo, or a Switch Pro on Windows, got a controller whose gyro did nothing, with nothing anywhere saying why: the client shipped ~250 Hz of Motion datagrams and the host parsed and discarded every one. `GamepadPref::has_motion()` answers whether a backend has a motion plane at all. The SDL client checks it on the first gyro sample: it logs one line naming the resolved backend and pointing at the fix (pick a DualSense-class controller type), then stops sending. Once per slot, not per sample — this path runs at the pad's sensor rate. `Auto` deliberately answers true. It means "unknown" — an old host that omitted the echo, which may well have resolved a DualSense — and suppressing motion on unknown would silently break working gyro, a worse failure than sending datagrams nobody reads. The predicate is an exhaustive match so a new backend has to state its answer rather than inherit one, and a table test pins both halves: a false negative kills working motion, a false positive keeps the void open, and both are silent. Owed: the plan wants this surfaced as a one-line UI hint, not just a log line. Apple already stores `resolvedGamepad` and Android needs the plumb; neither is done here, and both want their own gate. Gate (Linux CI image): fmt, build, clippy --all-targets -D warnings, and the test suites — green, with the new capability test observed running.