Description
During portrait streaming investigation on 2026-05-14, dd_resolution_option=auto was not switching the VDD resolution despite correct config. Root cause: Moonlight was passing --no-game-optimization which suppresses the optimizeGameSettings=true signal that Sunshine requires before it applies the auto resolution switch. Fixed in v2.0.41 by removing the flag.
The removal is not documented. If someone adds it back (performance testing, old template copy), portrait streaming silently breaks — VDD stays at landscape, no error in any log, only symptom is wrong capture resolution in Sunshine logs.
Action: add a code comment in pkg/client/moonlight.go explaining the invariant: do not add --no-game-optimization, it suppresses optimizeGameSettings=true which Sunshine requires for dd_resolution_option=auto. Portrait streams silently render at landscape resolution without it.