ラズパイのＨＤＭＩを途中でつなぐとディスプレイが映らない問題
https://raspberrypi.stackexchange.com/questions/96714/ubuntu-mate-pi-not-connecting-to-monitor
https://ubuntu-mate.community/t/hdmi-audio-help/7988
https://qiita.com/karaage0703/items/97808dfb957b3312b649
#ラズパイ