You should be able to use glTextureSubImage3D to upload faces to a cube map texture where zoffset is the cube map face since the 2D version does not have a target argument in DSA. This was discussed a bit on #dri-devel and it seemed like the code for glTextureSubImage3D was wrong. I believe someone attempted to push a fix it but I'm unable to build mesa from scratch at the moment. ps: I'm not sure what driver to select with intel hd 5500, please change it to the appropriate and remove this message if it's wrong.
This is the fix I pushed: http://cgit.freedesktop.org/mesa/mesa/commit/?id=2259b111003f2e8c55cae42677ec45345fb1b6e3 As there's no piglit coverage of dsa texture stuff right now, no idea if it helps. But it should.
There's few DSA tests that call this function and they pass, I'm resolving this as fixed. If you still experience problems with this, please reopen!
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.