And it works. Very nice. One showstopper was to figure out why my initial code didn't work. Turns out the transpose seems to not like DRM_FORMAT_BGR888, framebuffers as target when transposing. The resulting transposed framebuffer is grayish with those typical diagonally garbled output you'd expect if a pitch isn't correct. Setting the target FB to DRM_FORMAT_ABGR8888 fixes it, but now requires my writeback-using JPEG encoder to handle ABGR in addition to BGR.
The driver code suggests that all formats the writeback supports should work with transpose, so I'm not sure if I'm doing something stupid or if that's a limitation.
Statistics: Posted by dividuum — Thu Nov 28, 2024 12:43 pm