This caused us to update the indirect texture information in shaders more often than we needed to, which probably doesn't matter in practice since it's only used in ubershaders and copyyscale and stride are generally only updated before EFB/XFB copies, which generally will have other changes afterwards.
As far as I can tell, it has nothing to do with the mipmap/half_scale functionality, but does change based on the width of the destination texture (and the destination texture is half the width if half_scale is set). The comment that was there (which dates back to the initial megacommit) seems to not have accounted for the width aspect; it was first used as an actual stride in bbbe898839 (the first commit that used it at all).
The whole ownership model was getting a bit of a mess, with a some
of special cases to deal with. And I'm planning to make it even more
complex in the future.
So here is some upfront work to convert it over to reference counted
pointers.
Pokechu22
Dentomologist
Admiral H. Curtiss
Scott Mansell
Robin Kertels