[Linaro-mm-sig] [RFC 0/4] Atomic Display Framework

[Rob Clark]

On Thu, Aug 29, 2013 at 3:58 AM, Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
>> Imo we should just convert primary planes to real planes so that we
>> can do the same table-based checking for them as we do for secondary
>> planes right now.
>
> My plan for i915 is to convert them to drm_planes but first keep them
> hidden via Rob's private plane mechanism.
>
> After that we need to figure out how we can expose them to userspace w/o
> risking breaking stuff too much. Maybe a new ioctl to enumerate private
> planes only? And the maybe only accept direct use of private planes via
> the atomic API, not through the old setplane API. Or if people want to
> use setplane we could add a flag there indicating that the user is aware
> of private planes and wants to use them.

just fwiw, my thinking for private/primary[1] planes was to add a new
array at the end of getplaneresources.  This is really all we need.
Old userspace doesn't see the new field, and continues on happily.
New userspace sees the primary planes (and their possible_crtcs), and
realizes that if it is not using a crtc, it can possibly grab that
plane for other use.

BR,
-R

[1] I think "primary" is actually a better name, despite the fact that
I initially called 'em "private"