drm/doc: More fine-tuning on userspace review requirements

With Eric's patch

commit ba6e798ecf
Author: Eric Anholt <eric@anholt.net>
Date:   Wed Apr 24 11:56:17 2019 -0700

    drm/doc: Document expectation that userspace review looks at kernel uAPI.

there's been concerns raised that we expect userspace people to do
in-depth kernel patch review. That's not reasonable, same way kernel
people can't review all the userspace we have. Try to clarify
expectations a bit more.

Cc: Eric Anholt <eric@anholt.net>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: contact@emersion.fr
Cc: wayland-devel@lists.freedesktop.org
Acked-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190521084849.27452-1-daniel.vetter@ffwll.ch

Documentation/gpu/drm-uapi.rst

@@ -85,9 +85,9 @@ leads to a few additional requirements:
 - The userspace side must be fully reviewed and tested to the standards of that
   userspace project. For e.g. mesa this means piglit testcases and review on the
   mailing list. This is again to ensure that the new interface actually gets the
-  job done.  The userspace-side reviewer should also provide at least an
+  job done.  The userspace-side reviewer should also provide an Acked-by on the
-  Acked-by on the kernel uAPI patch indicating that they've looked at how the
+  kernel uAPI patch indicating that they believe the proposed uAPI is sound and
-  kernel side is implementing the new feature being used.
+  sufficiently documented and validated for userspace's consumption.
 
 - The userspace patches must be against the canonical upstream, not some vendor
   fork. This is to make sure that no one cheats on the review and testing