drm/plane-helper: Add the missing declaration of drm_atomic_state

Add the missing declaration of struct drm_atomic_state to fix the
compile error below:

error: 'struct drm_atomic_state' declared in

drm/plane-helper: Add the missing declaration of drm_atomic_state

Add the missing declaration of struct drm_atomic_state to fix the
compile error below:

error: 'struct drm_atomic_state' declared inside parameter
list will not be visible outside of this definition or declaration [-Werror]

Signed-off-by: Ma Jun <majun@amd.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 8401bd361f59 ("drm/plane-helper: Add a drm_plane_helper_atomic_check() helper")
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.1+
Link: https://patchwork.freedesktop.org/patch/msgid/20221216030526.1335609-1-majun@amd.com

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drm/plane-helper: Provide DRM_PLANE_NON_ATOMIC_FUNCS initializer macro

Provide DRM_PLANE_NON_ATOMIC_FUNCS, which initializes plane functions
of non-atomic drivers to default values. The macro is not

drm/plane-helper: Provide DRM_PLANE_NON_ATOMIC_FUNCS initializer macro

Provide DRM_PLANE_NON_ATOMIC_FUNCS, which initializes plane functions
of non-atomic drivers to default values. The macro is not supposed to
be used in new code, but helps with documenting and finding existing
users.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Lyude Paul <lyude@redhat.com> # nouveau
Link: https://patchwork.freedesktop.org/patch/msgid/20220909105947.6487-5-tzimmermann@suse.de

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drm/plane-helper: Add a drm_plane_helper_atomic_check() helper

Provides a default plane state check handler for primary planes that are a
fullscreen scanout buffer and whose state scale and position

drm/plane-helper: Add a drm_plane_helper_atomic_check() helper

Provides a default plane state check handler for primary planes that are a
fullscreen scanout buffer and whose state scale and position can't change.

There are some drivers that duplicate this logic in their helpers, such as
simpledrm and ssd130x. Factor out this common code into a plane helper and
make drivers use it.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220913162307.121503-1-javierm@redhat.com

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drm/plane-helper: Export individual helpers

Export the individual plane helpers that make up the plane functions and
align the naming with other helpers. The plane helpers are for non-atomic
modeset

drm/plane-helper: Export individual helpers

Export the individual plane helpers that make up the plane functions and
align the naming with other helpers. The plane helpers are for non-atomic
modesetting and exporting them will simplify a later conversion of drivers
to atomic modesetting.

With struct drm_plane_funcs removed from drm_plane_helper.h, also remove
the include statements. It only needs linux/types.h for uint32_t and a
number of forward declarations.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220720083058.15371-6-tzimmermann@suse.de

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drm/atomic-helper: Move DRM_PLANE_HELPER_NO_SCALING to atomic helpers

The macro DRM_PLANE_HELPER_NO_SCALING is only useful with the interfaces
in drm_atomic_helper.h, but defined in drm_plane_helper

drm/atomic-helper: Move DRM_PLANE_HELPER_NO_SCALING to atomic helpers

The macro DRM_PLANE_HELPER_NO_SCALING is only useful with the interfaces
in drm_atomic_helper.h, but defined in drm_plane_helper.h. So half of
DRM includes the latter header file for using this macro. Move the macro
and remove the include statements.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220720083058.15371-3-tzimmermann@suse.de

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drm: Unexport drm_plane_helper_check_update

It's for legacy drivers only (atomic ones should use
drm_atomic_helper_check_plane_state() instead), and there's no users
left except the one in the prima

drm: Unexport drm_plane_helper_check_update

It's for legacy drivers only (atomic ones should use
drm_atomic_helper_check_plane_state() instead), and there's no users
left except the one in the primary plane helpers.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181004202446.22905-18-daniel.vetter@ffwll.ch

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drm: Unexport primary plane helpers

Well except the destroy helper, which isn't really a primary helper
but generally useful, if mislabelled.

v2: Keep some of the nice comments about the limitation

drm: Unexport primary plane helpers

Well except the destroy helper, which isn't really a primary helper
but generally useful, if mislabelled.

v2: Keep some of the nice comments about the limitations of the
primarmy plane helpers, and put them into the kerneldoc for
drm_crtc_init() (Sam).

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181005094732.31353-1-daniel.vetter@ffwll.ch

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drm: Remove transitional helpers

With armada the last bigger driver that realistically needed these to
convert from legacy kms to atomic is converted. These helpers have
been broken more often than

drm: Remove transitional helpers

With armada the last bigger driver that realistically needed these to
convert from legacy kms to atomic is converted. These helpers have
been broken more often than not the past 2 years, and as this little
patch series shows, tricked a bunch of people into using the wrong
helpers for their functions.

Aside: I think a lot more drivers should be using the device-level
drm_atomic_helper_shutdown/suspend/resume helpers and related
functions. In almost all the cases they get things exactly right.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181004202446.22905-16-daniel.vetter@ffwll.ch

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drm: add missing ctx argument to plane transitional helpers

In commits:
34a2ab5e0689 ("drm: Add acquire ctx parameter to ->update_plane")
1931529448bc ("drm: Add acquire ctx parameter to ->plane_dis

drm: add missing ctx argument to plane transitional helpers

In commits:
34a2ab5e0689 ("drm: Add acquire ctx parameter to ->update_plane")
1931529448bc ("drm: Add acquire ctx parameter to ->plane_disable")

a pointer to a drm_modeset_acquire_ctx structure was added as an
argument to the method prototypes. The transitional helpers are
supposed to be directly plugged in as implementations of these
methods, but doing so generates a warning. Add the missing
argument.

A number of buggy users were added for drm_plane_helper_disable()
which need to be fixed up for this change, which we do by passing
a NULL ctx argument.

Fixes: 1931529448bc ("drm: Add acquire ctx parameter to ->plane_disable")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/E1fa1Zr-0005gT-VF@rmk-PC.armlinux.org.uk

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drm: Don't pass clip to drm_atomic_helper_check_plane_state()

Move the plane clip rectangle handling into
drm_atomic_helper_check_plane_state(). Drivers no longer
have to worry about such mundane de

drm: Don't pass clip to drm_atomic_helper_check_plane_state()

Move the plane clip rectangle handling into
drm_atomic_helper_check_plane_state(). Drivers no longer
have to worry about such mundane details.

v2: Convert armada, rcar, and sun4i as well
v3: Resolve simple_kms_helper conflict

Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: Mali DP Maintainers <malidp@foss.arm.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: CK Hu <ck.hu@mediatek.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Sinclair Yeh <syeh@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Archit Taneja <architt@codeaurora.org> #msm
Link: https://patchwork.freedesktop.org/patch/msgid/20180123170857.13818-5-ville.syrjala@linux.intel.com
Acked-by: Liviu Dudau <liviu.dudau@arm.com> #hdlcd,malidp
Acked-by: Philipp Zabel <p.zabel@pengutronix.de> #imx,mtk
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com> #vmwgfx
Acked-by: Neil Armstrong <narmstrong@baylibre.com> #meson
Acked-by: Shawn Guo <shawnguo@kernel.org> #zte

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drm: Move drm_plane_helper_check_state() into drm_atomic_helper.c

drm_plane_helper_check_update() isn't a transitional helper, so let's
rename it to drm_atomic_helper_check_plane_state() and move it

drm: Move drm_plane_helper_check_state() into drm_atomic_helper.c

drm_plane_helper_check_update() isn't a transitional helper, so let's
rename it to drm_atomic_helper_check_plane_state() and move it into
drm_atomic_helper.c.

v2: Fix the WARNs about plane_state->crtc matching crtc_state->crtc

Cc: Daniel Vetter <daniel@ffwll.ch>
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171101201619.6175-1-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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drm: Check crtc_state->enable rather than crtc->enabled in drm_plane_helper_check_state()

drm_plane_helper_check_state() is supposed to do things the atomic way,
so it should not be inspecting crtc-

drm: Check crtc_state->enable rather than crtc->enabled in drm_plane_helper_check_state()

drm_plane_helper_check_state() is supposed to do things the atomic way,
so it should not be inspecting crtc->enabled. Rather we should be
looking at crtc_state->enable.

We have a slight complication due to drm_plane_helper_check_update()
reusing drm_plane_helper_check_state() for non-atomic drivers. Thus
we'll have to pass the crtc_state in manally and construct a fake
crtc_state in drm_plane_helper_check_update().

v2: Fix the WARNs about plane_state->crtc matching crtc_state->crtc

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171101201558.6059-1-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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drm: Add acquire ctx parameter to ->plane_disable

Nouveau had a few direct calls to ->disable_plane, I replaced those
with drm_plane_force_disable. Same story for shmob.

Otherwise no code changes.

drm: Add acquire ctx parameter to ->plane_disable

Nouveau had a few direct calls to ->disable_plane, I replaced those
with drm_plane_force_disable. Same story for shmob.

Otherwise no code changes.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322215058.8671-5-daniel.vetter@ffwll.ch

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drm: Add acquire ctx parameter to ->update_plane

Just rolling it out, no code change here.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Rob Clark <robdclark@gmai

drm: Add acquire ctx parameter to ->update_plane

Just rolling it out, no code change here.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Eric Anholt <eric@anholt.net>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322215058.8671-3-daniel.vetter@ffwll.ch

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drm/kms-helpers: Extract drm_modeset_helper.[hc]

While reviewing docs I spotted that we have a few functions that
really just don't fit into their containing helper library section.
Extract them and

drm/kms-helpers: Extract drm_modeset_helper.[hc]

While reviewing docs I spotted that we have a few functions that
really just don't fit into their containing helper library section.
Extract them and shovel them all into a new library for random one-off
aux stuff.

v2: Remove wrongly added files for real.

Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471034937-651-3-git-send-email-daniel.vetter@ffwll.ch

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drm/plane-helper: Add drm_plane_helper_check_state()

Add a version of drm_plane_helper_check_update() which takes a plane
state instead of having the caller pass in everything.

And to reduce code d

drm/plane-helper: Add drm_plane_helper_check_state()

Add a version of drm_plane_helper_check_update() which takes a plane
state instead of having the caller pass in everything.

And to reduce code duplication, let's reimplement
drm_plane_helper_check_update() in terms of the new function, by
having a tempororary plane state on the stack.

v2: Add a note that the functions modifies the state (Chris)
v3: Fix drm_plane_helper_check_update() y coordinates (Daniel Kurtz)

Cc: Daniel Kurtz <djkurtz@chromium.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org> (v2)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1470642910-14073-1-git-send-email-ville.syrjala@linux.intel.com

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drm: Deal with rotation in drm_plane_helper_check_update()

drm_plane_helper_check_update() needs to account for the plane rotation
for correct clipping/scaling calculations. Do so.

There was an ear

drm: Deal with rotation in drm_plane_helper_check_update()

drm_plane_helper_check_update() needs to account for the plane rotation
for correct clipping/scaling calculations. Do so.

There was an earlier attempt [1] to add this into
intel_check_primary_plane() but I requested that it'd be put into the
helper instead. An updated patch never materialized AFAICS, so I went
ahead and cooked one up myself.

v2: Deal with new drm_plane_helper_check_update() callers

[1] https://patchwork.freedesktop.org/patch/65177/
Cc: Nabendu Maiti <nabendu.bikash.maiti@intel.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: CK Hu <ck.hu@mediatek.com>
Cc: Mark Yao <mark.yao@rock-chips.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1466172790-10025-1-git-send-email-ville.syrjala@linux.intel.com

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drm: Reorganize helper vtables and their docs

Currently we have 4 helper libraries (probe, crtc, plane & atomic)
that all use the same helper vtables. And that's by necessity since we
don't want to

drm: Reorganize helper vtables and their docs

Currently we have 4 helper libraries (probe, crtc, plane & atomic)
that all use the same helper vtables. And that's by necessity since we
don't want to litter the core structs with one ops pointer per helper
library. Also often the reuse the same hooks (like atomic does, to
facilite conversion from existing drivers using crtc and plane
helpers).

Given all that it doesn't make sense to put the docs for these next to
specific helpers. Instead extract them into a new header file and
section in the docbook, and add references to them everywhere.

Unfortunately kernel-doc complains when an include directive doesn't
find anything (and it does by dumping crap into the output file). We
have to remove the now empty includes to avoid that, instead of leaving
them in for future proofing.

v2: More OCD in ordering functions.

v3: Spelling plus collate copyright headers properly.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449218769-16577-4-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Thierry Reding <treding@nvidia.com>

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drm/atomic: Make prepare_fb/cleanup_fb only take state, v3.

This removes the need to separately track fb changes i915.
That will be done as a separate commit, however.

Changes since v1:
- Add dri-d

drm/atomic: Make prepare_fb/cleanup_fb only take state, v3.

This removes the need to separately track fb changes i915.
That will be done as a separate commit, however.

Changes since v1:
- Add dri-devel to cc.
- Fix a check in intel's prepare and cleanup fb to take rotation
into account.
Changes since v2:
- Split out i915 changes to a separate commit.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
[danvet: Squash in msm fixup from Maarten.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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drm/plane: Remove redundant extern

Use of the extern keyword for function prototypes is unnecessary, so it
can be removed.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel V

drm/plane: Remove redundant extern

Use of the extern keyword for function prototypes is unnecessary, so it
can be removed.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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drm: make crtc/encoder/connector/plane helper_private a const pointer

They're only used to store const pointers anyway. This helps to keep
Ville and the compiler happy.

Signed-off-by: Jani Nikula <

drm: make crtc/encoder/connector/plane helper_private a const pointer

They're only used to store const pointers anyway. This helps to keep
Ville and the compiler happy.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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drm/plane-helper: unexport drm_primary_helper_create_plane

We shouldn't tempt driver writers into using this since it uses a
default format list which is likely wrong. And when that's done we can
si

drm/plane-helper: unexport drm_primary_helper_create_plane

We shouldn't tempt driver writers into using this since it uses a
default format list which is likely wrong. And when that's done we can
simplify the code a bit, too.

Noticed while reviewing a patch from Laurent.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

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drm: Pass in new and old plane state to prepare_fb and cleanup_fb

Use cases like rotation require these hooks to have some context so they
know how to prepare and cleanup the frame buffer correctly.

drm: Pass in new and old plane state to prepare_fb and cleanup_fb

Use cases like rotation require these hooks to have some context so they
know how to prepare and cleanup the frame buffer correctly.

For i915 specifically, object backing pages need to be mapped differently
for different rotation modes and the driver needs to know which mapping to
instantiate and which to tear down when transitioning between them.

v2: Made passed in states const. (Daniel Vetter)

[airlied: add mdp5 and atmel fixups]
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

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drm/plane: Add optional ->atomic_disable() callback

In order to prevent drivers from having to perform the same checks over
and over again, add an optional ->atomic_disable callback which the core
c

drm/plane: Add optional ->atomic_disable() callback

In order to prevent drivers from having to perform the same checks over
and over again, add an optional ->atomic_disable callback which the core
calls under the right circumstances.

v2: pass old state and detect edges to avoid calling ->atomic_disable on
already disabled planes, remove redundant comment (Daniel Vetter)

v3: rename helper to drm_atomic_plane_disabling() to clarify that it is
checking for transitions, move helper to drm_atomic_helper.h, clarify
check for !old_state and its relation to transitional helpers

Here's an extract from some discussion rationalizing the behaviour (for
a full version, see the reference below):

> > Hm, thinking about this some more this will result in a slight difference
> > in behaviour, at least when drivers just use the helper ->reset functions
> > but don't disable everything:
> > - With transitional helpers we assume we know nothing and call
> > ->atomic_disable.
> > - With atomic old_state->crtc == NULL in the same situation right after
> > boot-up, but we asssume the plane is really off and _dont_ call
> > ->atomic_disable.
> >
> > Should we instead check for (old_state && old_state->crtc) and state that
> > drivers need to make sure they don't have stuff hanging around?
>
> I don't think we can check for old_state because otherwise this will
> always return false, whereas we really want it to force-disable planes
> that could be on (lacking any more accurate information). For
> transitional helpers anyway.
>
> For the atomic helpers, old_state will never be NULL, but I'd assume
> that the driver would reconstruct the current state in ->reset().

By the way, the reason for why old_state can be NULL with transitional
helpers is the ordering of the steps in the atomic transition. Currently
the Tegra patches do this (based on your blog post and the Exynos proto-
type):

1) atomic conversion, phase 1:
- implement ->atomic_{check,update,disable}()
- use drm_plane_helper_{update,disable}()

2) atomic conversion, phase 2:
- call drm_mode_config_reset() from ->load()
- implement ->reset()

That's only a partial list of what's done in these steps, but that's the
only relevant pieces for why old_state is NULL.

What happens is that without ->reset() implemented there won't be any
initial state, hence plane->state (the old_state here) will be NULL the
first time atomic state is applied.

We could of course reorder the sequence such that drivers are required
to hook up ->reset() before they can (or at the same as they) hook up
the transitional helpers. We could add an appropriate WARN_ON to this
helper to make that more obvious.

However, that will not solve the problem because it only gets rid of the
special case. We still don't know whether old_state->crtc == NULL is the
current state or just the initial default.

So no matter which way we do this, I don't see a way to get away without
requiring specific semantics from drivers. They would be that:

- drivers recreate the correct state in ->reset() so that
old_state->crtc != NULL if the plane is really enabled

or

- drivers have to ensure that the real state in fact mirrors the
initial default as encoded in the state (plane disabled)

References: http://lists.freedesktop.org/archives/dri-devel/2015-January/075578.html
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>

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drm/plane: Make ->atomic_update() mandatory

There is no use-case where it would be useful for drivers not to
implement this function and the transitional plane helpers already
require drivers to pro

drm/plane: Make ->atomic_update() mandatory

There is no use-case where it would be useful for drivers not to
implement this function and the transitional plane helpers already
require drivers to provide an implementation.

v2: add new requirement to kerneldoc

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>

show more ...