FuguredFigured it out myself.
the tvThe TV has three modes for remote power on:
- offOff
- throughThrough network
- throughThrough application (adbADB)
ifIf you choose the third option, the tv periodlyTV periodically "pre power-power on" itself so that the user can send adban ADB command to it to actually turn on the screen, which causes my HDMI cable periodlyperiodically receiving signals of a new device.
(still not sure why the tvTV can't be always "pre powered-powered on")
But if you choose the second option, everything is fine.