[PATCH] drm: pre-fill getfb2 modifier array with INVALID

[Simon Ser]

On Thursday, November 11th, 2021 at 13:50, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:

> On Thu, Nov 11, 2021 at 10:10:54AM +0000, Simon Ser wrote:
> > User-space shouldn't look up the modifier array when the modifier
> > flag is missing, but at the moment no docs make this clear (working
> > on it). Right now the modifier array is pre-filled with zeroes, aka.
> > LINEAR. Instead, pre-fill with INVALID to avoid footguns.
> >
> > This is a uAPI change, but OTOH any user-space which looks up the
> > modifier array without checking the flag is broken already, so
> > should be fine.
> >
> > Signed-off-by: Simon Ser <contact at emersion.fr>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Pekka Paalanen <ppaalanen at gmail.com>
> > Cc: Daniel Stone <daniels at collabora.com>
>
> Isn't this going to break the test where we pass the get
> getfb2 result back into addfb2?

Shouldn't be the case, since the kernel will ignore modifiers if the
flag isn't set.