Everyone knows them, except all the new folks joining from the ARM
side haven't lived through all the pain of the past years and are
entirely surprised when I raise this. Definitely time to document
this.

Last time this was a big discussion was about 6 years ago, when qcom
tried to land a kernel driver without userspace. Dave Airlie made the
rules really clear:

http://airlied.livejournal.com/73115.html

This write-up here is essentially what I've put into a presentation a
while ago, which was also reviewed by Dave:

http://blog.ffwll.ch/2015/05/gfx-kernel-upstreaming-requirements.html

v2: Fix typos Eric&Rob spotted.

v3: Nitpick from Jani.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Sinclair Yeh <syeh@vmware.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Mark Yao <mark.yao@rock-chips.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: CK Hu <ck.hu@mediatek.com>
Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Maxime Ripard  <maxime.ripard@free-electrons.com>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: NDave Airlie <airlied@gmail.com>
Reviewed-by: NRob Clark <robdclark@gmail.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NEric Anholt <eric@anholt.net>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>