Hi Ayaka, Le mercredi 27 février 2019 à 23:13 +0800, Ayaka a écrit : > Last time in FOSDEM, kwiboo and I talk some problems of the request > API and stateless decoder, I say the a method to describe a buffer > with many offsets as the buffer meta data would solve the most of > problems we talked, but I have no idea on how to implement it. And I > think a buffer meta describing a buffer with many offsets would solve > this problem as well. for single allocation case, the only supported in-between plane padding is an evenly distributed padding. This padding is communicated to userspace through S_FMT, by extending the width and height. Userspace then reads the display width/height through G_SELECTION API. For anything else, the MPLANE structure with one of the multi-plane format can "express" such buffer, though from userspace they are exposed as two memory pointer or DMABuf FDs (which make importation complicated if the buffer should initially be within a single allocation). I'll leave to kernel dev the task to explain what is feasible there (e.g. sub-buffering, etc.) Nicolas
