Created attachment 145171 [details] [review]
si_video_buffer_create fixups

I've traced this to the si_video_buffer_create function, which makes multiple
pipe_resources use the same buffer, but doesn't update the bo_size or make sure
si_can_invalidate_texture returns false for those resources. So
si_texture_transfer_map may allocate a new buffer of the original bo_size,
which is smaller than the combined size of the resources => its CPU mapping
doesn't always cover the calculated address.

This quick'n'dirty patch prevents the crash, but now totem just hangs for me.