Hey,
The connector/encoder funcs you do have to pass to drm_writeback_connector_init() can't use any of the shared driver infrastructure that assume a certain inheritance.
See also my reply to Laurent [1].
It well might be that we all misunderstand your design. Do you have a complete intel drm_writeback implementation based on this patchset? It would be easier to judge if the approach is correct seeing your target.
That would be up to Suraj Kandpal.
I have floated the intel drm_writeback implementation. Please refer to [1] to get a better understanding of how we are implementing writeback functionality.
[1] https://patchwork.freedesktop.org/series/100617/
Thanks, Suraj Kandpal