On 9/7/26 18:35, Neil Armstrong wrote: > Yes if it's a discrete SBU mux, gpio-sbu-mux was designed for that, and > keep the nb7vpq904m and just drop the SBU link to the redriver and replace > it with a link to the SBU mux instead.
That fixed it. A gpio-sbu-mux node on TLMM 8 (select) / TLMM 9 (enable), the connector's SBU graph endpoint moved from the nb7vpq904m to it, and the nb7vpq904m's enable-gpios dropped (TLMM 9 is the mux enable, not the redriver enable). nb7vpq904m stays as the SS retimer-switch. Reversed orientation now brings DP up reliably - one normal plug and three reversed re-plugs, all four train to 4 lanes and stay connected, no more DPCD read timeout. Normal orientation is unchanged. This board (Retroid Pocket 5) isn't upstream yet, so the fix lands downstream for now, but thanks a lot for the quick pointer - "nb7vpq904m alone doesn't switch SBU" was exactly the piece I was missing. BurningHoryd
