[PATCH v3 5/7] drm/panfrost: Add a new ioctl to submit batches

[Boris Brezillon]

On Fri, 2 Jul 2021 12:49:55 -0400
Alyssa Rosenzweig <alyssa at collabora.com> wrote:

> > > Why is there padding instead of putting point first?  
> > 
> > We can move the point field first, but we need to keep the explicit
> > padding: the struct has to be 64bit aligned because of the __u64 field
> > (which the compiler takes care of) but if we don't have an explicit
> > padding, the unused 32bits are undefined, which might cause trouble if
> > we extend the struct at some point, since we sort of expect that old
> > userspace keep this unused 32bit slot to 0, while new users set
> > non-zero values if they have to.  
> 
> Makes sense. Reordering still probably makes sense.

Actually, I can't re-order if I want the new in_syncs parser to work
with the old ioctl(), which you and Steven asked me to do :-).