https://bugs.winehq.org/show_bug.cgi?id=38274
--- Comment #9 from Stefan Dösinger stefan@codeweavers.com --- I haven't checked the spec, but I don't think this is allowed. OpenGL only allows block-aligned updates, except in cases where the resource is smaller than the block size (e.g. mipmaps). Even then you have to supply a full block of data of course.