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-rw-r--r--Documentation/gpu/bridge/dw-hdmi.rst15
-rw-r--r--Documentation/gpu/drm-internals.rst113
-rw-r--r--Documentation/gpu/drm-kms-helpers.rst40
-rw-r--r--Documentation/gpu/drm-kms.rst264
-rw-r--r--Documentation/gpu/drm-mm.rst41
-rw-r--r--Documentation/gpu/drm-uapi.rst40
-rw-r--r--Documentation/gpu/i915.rst9
-rw-r--r--Documentation/gpu/index.rst4
-rw-r--r--Documentation/gpu/introduction.rst46
-rw-r--r--Documentation/gpu/kms-properties.csv5
-rw-r--r--Documentation/gpu/meson.rst61
-rw-r--r--Documentation/gpu/todo.rst407
-rw-r--r--Documentation/gpu/vc4.rst89
13 files changed, 978 insertions, 156 deletions
diff --git a/Documentation/gpu/bridge/dw-hdmi.rst b/Documentation/gpu/bridge/dw-hdmi.rst
new file mode 100644
index 000000000000..486faadf00af
--- /dev/null
+++ b/Documentation/gpu/bridge/dw-hdmi.rst
@@ -0,0 +1,15 @@
+=======================================================
+ drm/bridge/dw-hdmi Synopsys DesignWare HDMI Controller
+=======================================================
+
+Synopsys DesignWare HDMI Controller
+===================================
+
+This section covers everything related to the Synopsys DesignWare HDMI
+Controller implemented as a DRM bridge.
+
+Supported Input Formats and Encodings
+-------------------------------------
+
+.. kernel-doc:: include/drm/bridge/dw_hdmi.h
+ :doc: Supported input formats and encodings
diff --git a/Documentation/gpu/drm-internals.rst b/Documentation/gpu/drm-internals.rst
index e35920db1f4c..babfb6143bd9 100644
--- a/Documentation/gpu/drm-internals.rst
+++ b/Documentation/gpu/drm-internals.rst
@@ -140,12 +140,12 @@ Device Instance and Driver Handling
.. kernel-doc:: drivers/gpu/drm/drm_drv.c
:doc: driver instance overview
-.. kernel-doc:: drivers/gpu/drm/drm_drv.c
- :export:
-
.. kernel-doc:: include/drm/drm_drv.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_drv.c
+ :export:
+
Driver Load
-----------
@@ -240,120 +240,21 @@ drivers.
.. kernel-doc:: drivers/gpu/drm/drm_pci.c
:export:
-.. kernel-doc:: drivers/gpu/drm/drm_platform.c
- :export:
-
Open/Close, File Operations and IOCTLs
======================================
-Open and Close
---------------
-
-Open and close handlers. None of those methods are mandatory::
-
- int (*firstopen) (struct drm_device *);
- void (*lastclose) (struct drm_device *);
- int (*open) (struct drm_device *, struct drm_file *);
- void (*preclose) (struct drm_device *, struct drm_file *);
- void (*postclose) (struct drm_device *, struct drm_file *);
-
-The firstopen method is called by the DRM core for legacy UMS (User Mode
-Setting) drivers only when an application opens a device that has no
-other opened file handle. UMS drivers can implement it to acquire device
-resources. KMS drivers can't use the method and must acquire resources
-in the load method instead.
-
-Similarly the lastclose method is called when the last application
-holding a file handle opened on the device closes it, for both UMS and
-KMS drivers. Additionally, the method is also called at module unload
-time or, for hot-pluggable devices, when the device is unplugged. The
-firstopen and lastclose calls can thus be unbalanced.
-
-The open method is called every time the device is opened by an
-application. Drivers can allocate per-file private data in this method
-and store them in the struct :c:type:`struct drm_file
-<drm_file>` driver_priv field. Note that the open method is
-called before firstopen.
-
-The close operation is split into preclose and postclose methods.
-Drivers must stop and cleanup all per-file operations in the preclose
-method. For instance pending vertical blanking and page flip events must
-be cancelled. No per-file operation is allowed on the file handle after
-returning from the preclose method.
-
-Finally the postclose method is called as the last step of the close
-operation, right before calling the lastclose method if no other open
-file handle exists for the device. Drivers that have allocated per-file
-private data in the open method should free it here.
-
-The lastclose method should restore CRTC and plane properties to default
-value, so that a subsequent open of the device will not inherit state
-from the previous user. It can also be used to execute delayed power
-switching state changes, e.g. in conjunction with the :ref:`vga_switcheroo`
-infrastructure. Beyond that KMS drivers should not do any
-further cleanup. Only legacy UMS drivers might need to clean up device
-state so that the vga console or an independent fbdev driver could take
-over.
-
File Operations
---------------
-.. kernel-doc:: drivers/gpu/drm/drm_fops.c
+.. kernel-doc:: drivers/gpu/drm/drm_file.c
:doc: file operations
-.. kernel-doc:: drivers/gpu/drm/drm_fops.c
- :export:
-
-IOCTLs
-------
-
-struct drm_ioctl_desc \*ioctls; int num_ioctls;
- Driver-specific ioctls descriptors table.
-
-Driver-specific ioctls numbers start at DRM_COMMAND_BASE. The ioctls
-descriptors table is indexed by the ioctl number offset from the base
-value. Drivers can use the DRM_IOCTL_DEF_DRV() macro to initialize
-the table entries.
-
-::
-
- DRM_IOCTL_DEF_DRV(ioctl, func, flags)
-
-``ioctl`` is the ioctl name. Drivers must define the DRM_##ioctl and
-DRM_IOCTL_##ioctl macros to the ioctl number offset from
-DRM_COMMAND_BASE and the ioctl number respectively. The first macro is
-private to the device while the second must be exposed to userspace in a
-public header.
-
-``func`` is a pointer to the ioctl handler function compatible with the
-``drm_ioctl_t`` type.
-
-::
-
- typedef int drm_ioctl_t(struct drm_device *dev, void *data,
- struct drm_file *file_priv);
-
-``flags`` is a bitmask combination of the following values. It restricts
-how the ioctl is allowed to be called.
-
-- DRM_AUTH - Only authenticated callers allowed
-
-- DRM_MASTER - The ioctl can only be called on the master file handle
-
-- DRM_ROOT_ONLY - Only callers with the SYSADMIN capability allowed
-
-- DRM_CONTROL_ALLOW - The ioctl can only be called on a control
- device
-
-- DRM_UNLOCKED - The ioctl handler will be called without locking the
- DRM global mutex. This is the enforced default for kms drivers (i.e.
- using the DRIVER_MODESET flag) and hence shouldn't be used any more
- for new drivers.
+.. kernel-doc:: include/drm/drm_file.h
+ :internal:
-.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
+.. kernel-doc:: drivers/gpu/drm/drm_file.c
:export:
-
Misc Utilities
==============
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index 03040aa14fe8..c075aadd7078 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -37,10 +37,12 @@ Modeset Helper Reference for Common Vtables
===========================================
.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h
- :internal:
+ :doc: overview
.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h
- :doc: overview
+ :internal:
+
+.. _drm_atomic_helper:
Atomic Modeset Helper Functions Reference
=========================================
@@ -84,27 +86,27 @@ Legacy CRTC/Modeset Helper Functions Reference
Simple KMS Helper Reference
===========================
+.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c
+ :doc: overview
+
.. kernel-doc:: include/drm/drm_simple_kms_helper.h
:internal:
.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c
:export:
-.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c
- :doc: overview
-
fbdev Helper Functions Reference
================================
.. kernel-doc:: drivers/gpu/drm/drm_fb_helper.c
:doc: fbdev helpers
-.. kernel-doc:: drivers/gpu/drm/drm_fb_helper.c
- :export:
-
.. kernel-doc:: include/drm/drm_fb_helper.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_fb_helper.c
+ :export:
+
Framebuffer CMA Helper Functions Reference
==========================================
@@ -114,6 +116,8 @@ Framebuffer CMA Helper Functions Reference
.. kernel-doc:: drivers/gpu/drm/drm_fb_cma_helper.c
:export:
+.. _drm_bridges:
+
Bridges
=======
@@ -139,18 +143,20 @@ Bridge Helper Reference
.. kernel-doc:: drivers/gpu/drm/drm_bridge.c
:export:
+.. _drm_panel_helper:
+
Panel Helper Reference
======================
+.. kernel-doc:: drivers/gpu/drm/drm_panel.c
+ :doc: drm panel
+
.. kernel-doc:: include/drm/drm_panel.h
:internal:
.. kernel-doc:: drivers/gpu/drm/drm_panel.c
:export:
-.. kernel-doc:: drivers/gpu/drm/drm_panel.c
- :doc: drm panel
-
Display Port Helper Functions Reference
=======================================
@@ -217,6 +223,18 @@ EDID Helper Functions Reference
.. kernel-doc:: drivers/gpu/drm/drm_edid.c
:export:
+SCDC Helper Functions Reference
+===============================
+
+.. kernel-doc:: drivers/gpu/drm/drm_scdc_helper.c
+ :doc: scdc helpers
+
+.. kernel-doc:: include/drm/drm_scdc_helper.h
+ :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_scdc_helper.c
+ :export:
+
Rectangle Utilities Reference
=============================
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index 4d4068855ec4..bfecd21a8cdf 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -15,35 +15,271 @@ be setup by initializing the following fields.
- struct drm_mode_config_funcs \*funcs;
Mode setting functions.
-Mode Configuration
+Overview
+========
+
+.. kernel-render:: DOT
+ :alt: KMS Display Pipeline
+ :caption: KMS Display Pipeline Overview
+
+ digraph "KMS" {
+ node [shape=box]
+
+ subgraph cluster_static {
+ style=dashed
+ label="Static Objects"
+
+ node [bgcolor=grey style=filled]
+ "drm_plane A" -> "drm_crtc"
+ "drm_plane B" -> "drm_crtc"
+ "drm_crtc" -> "drm_encoder A"
+ "drm_crtc" -> "drm_encoder B"
+ }
+
+ subgraph cluster_user_created {
+ style=dashed
+ label="Userspace-Created"
+
+ node [shape=oval]
+ "drm_framebuffer 1" -> "drm_plane A"
+ "drm_framebuffer 2" -> "drm_plane B"
+ }
+
+ subgraph cluster_connector {
+ style=dashed
+ label="Hotpluggable"
+
+ "drm_encoder A" -> "drm_connector A"
+ "drm_encoder B" -> "drm_connector B"
+ }
+ }
+
+The basic object structure KMS presents to userspace is fairly simple.
+Framebuffers (represented by :c:type:`struct drm_framebuffer <drm_framebuffer>`,
+see `Frame Buffer Abstraction`_) feed into planes. One or more (or even no)
+planes feed their pixel data into a CRTC (represented by :c:type:`struct
+drm_crtc <drm_crtc>`, see `CRTC Abstraction`_) for blending. The precise
+blending step is explained in more detail in `Plane Composition Properties`_ and
+related chapters.
+
+For the output routing the first step is encoders (represented by
+:c:type:`struct drm_encoder <drm_encoder>`, see `Encoder Abstraction`_). Those
+are really just internal artifacts of the helper libraries used to implement KMS
+drivers. Besides that they make it unecessarily more complicated for userspace
+to figure out which connections between a CRTC and a connector are possible, and
+what kind of cloning is supported, they serve no purpose in the userspace API.
+Unfortunately encoders have been exposed to userspace, hence can't remove them
+at this point. Futhermore the exposed restrictions are often wrongly set by
+drivers, and in many cases not powerful enough to express the real restrictions.
+A CRTC can be connected to multiple encoders, and for an active CRTC there must
+be at least one encoder.
+
+The final, and real, endpoint in the display chain is the connector (represented
+by :c:type:`struct drm_connector <drm_connector>`, see `Connector
+Abstraction`_). Connectors can have different possible encoders, but the kernel
+driver selects which encoder to use for each connector. The use case is DVI,
+which could switch between an analog and a digital encoder. Encoders can also
+drive multiple different connectors. There is exactly one active connector for
+every active encoder.
+
+Internally the output pipeline is a bit more complex and matches today's
+hardware more closely:
+
+.. kernel-render:: DOT
+ :alt: KMS Output Pipeline
+ :caption: KMS Output Pipeline
+
+ digraph "Output Pipeline" {
+ node [shape=box]
+
+ subgraph {
+ "drm_crtc" [bgcolor=grey style=filled]
+ }
+
+ subgraph cluster_internal {
+ style=dashed
+ label="Internal Pipeline"
+ {
+ node [bgcolor=grey style=filled]
+ "drm_encoder A";
+ "drm_encoder B";
+ "drm_encoder C";
+ }
+
+ {
+ node [bgcolor=grey style=filled]
+ "drm_encoder B" -> "drm_bridge B"
+ "drm_encoder C" -> "drm_bridge C1"
+ "drm_bridge C1" -> "drm_bridge C2";
+ }
+ }
+
+ "drm_crtc" -> "drm_encoder A"
+ "drm_crtc" -> "drm_encoder B"
+ "drm_crtc" -> "drm_encoder C"
+
+
+ subgraph cluster_output {
+ style=dashed
+ label="Outputs"
+
+ "drm_encoder A" -> "drm_connector A";
+ "drm_bridge B" -> "drm_connector B";
+ "drm_bridge C2" -> "drm_connector C";
+
+ "drm_panel"
+ }
+ }
+
+Internally two additional helper objects come into play. First, to be able to
+share code for encoders (sometimes on the same SoC, sometimes off-chip) one or
+more :ref:`drm_bridges` (represented by :c:type:`struct drm_bridge
+<drm_bridge>`) can be linked to an encoder. This link is static and cannot be
+changed, which means the cross-bar (if there is any) needs to be mapped between
+the CRTC and any encoders. Often for drivers with bridges there's no code left
+at the encoder level. Atomic drivers can leave out all the encoder callbacks to
+essentially only leave a dummy routing object behind, which is needed for
+backwards compatibility since encoders are exposed to userspace.
+
+The second object is for panels, represented by :c:type:`struct drm_panel
+<drm_panel>`, see :ref:`drm_panel_helper`. Panels do not have a fixed binding
+point, but are generally linked to the driver private structure that embeds
+:c:type:`struct drm_connector <drm_connector>`.
+
+Note that currently the bridge chaining and interactions with connectors and
+panels are still in-flux and not really fully sorted out yet.
KMS Core Structures and Functions
=================================
-.. kernel-doc:: drivers/gpu/drm/drm_mode_config.c
- :export:
-
.. kernel-doc:: include/drm/drm_mode_config.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_mode_config.c
+ :export:
+
Modeset Base Object Abstraction
===============================
+.. kernel-render:: DOT
+ :alt: Mode Objects and Properties
+ :caption: Mode Objects and Properties
+
+ digraph {
+ node [shape=box]
+
+ "drm_property A" -> "drm_mode_object A"
+ "drm_property A" -> "drm_mode_object B"
+ "drm_property B" -> "drm_mode_object A"
+ }
+
+The base structure for all KMS objects is :c:type:`struct drm_mode_object
+<drm_mode_object>`. One of the base services it provides is tracking properties,
+which are especially important for the atomic IOCTL (see `Atomic Mode
+Setting`_). The somewhat surprising part here is that properties are not
+directly instantiated on each object, but free-standing mode objects themselves,
+represented by :c:type:`struct drm_property <drm_property>`, which only specify
+the type and value range of a property. Any given property can be attached
+multiple times to different objects using :c:func:`drm_object_attach_property()
+<drm_object_attach_property>`.
+
.. kernel-doc:: include/drm/drm_mode_object.h
:internal:
.. kernel-doc:: drivers/gpu/drm/drm_mode_object.c
:export:
-Atomic Mode Setting Function Reference
-======================================
+Atomic Mode Setting
+===================
-.. kernel-doc:: drivers/gpu/drm/drm_atomic.c
- :export:
+
+.. kernel-render:: DOT
+ :alt: Mode Objects and Properties
+ :caption: Mode Objects and Properties
+
+ digraph {
+ node [shape=box]
+
+ subgraph cluster_state {
+ style=dashed
+ label="Free-standing state"
+
+ "drm_atomic_state" -> "duplicated drm_plane_state A"
+ "drm_atomic_state" -> "duplicated drm_plane_state B"
+ "drm_atomic_state" -> "duplicated drm_crtc_state"
+ "drm_atomic_state" -> "duplicated drm_connector_state"
+ "drm_atomic_state" -> "duplicated driver private state"
+ }
+
+ subgraph cluster_current {
+ style=dashed
+ label="Current state"
+
+ "drm_device" -> "drm_plane A"
+ "drm_device" -> "drm_plane B"
+ "drm_device" -> "drm_crtc"
+ "drm_device" -> "drm_connector"
+ "drm_device" -> "driver private object"
+
+ "drm_plane A" -> "drm_plane_state A"
+ "drm_plane B" -> "drm_plane_state B"
+ "drm_crtc" -> "drm_crtc_state"
+ "drm_connector" -> "drm_connector_state"
+ "driver private object" -> "driver private state"
+ }
+
+ "drm_atomic_state" -> "drm_device" [label="atomic_commit"]
+ "duplicated drm_plane_state A" -> "drm_device"[style=invis]
+ }
+
+Atomic provides transactional modeset (including planes) updates, but a
+bit differently from the usual transactional approach of try-commit and
+rollback:
+
+- Firstly, no hardware changes are allowed when the commit would fail. This
+ allows us to implement the DRM_MODE_ATOMIC_TEST_ONLY mode, which allows
+ userspace to explore whether certain configurations would work or not.
+
+- This would still allow setting and rollback of just the software state,
+ simplifying conversion of existing drivers. But auditing drivers for
+ correctness of the atomic_check code becomes really hard with that: Rolling
+ back changes in data structures all over the place is hard to get right.
+
+- Lastly, for backwards compatibility and to support all use-cases, atomic
+ updates need to be incremental and be able to execute in parallel. Hardware
+ doesn't always allow it, but where possible plane updates on different CRTCs
+ should not interfere, and not get stalled due to output routing changing on
+ different CRTCs.
+
+Taken all together there's two consequences for the atomic design:
+
+- The overall state is split up into per-object state structures:
+ :c:type:`struct drm_plane_state <drm_plane_state>` for planes, :c:type:`struct
+ drm_crtc_state <drm_crtc_state>` for CRTCs and :c:type:`struct
+ drm_connector_state <drm_connector_state>` for connectors. These are the only
+ objects with userspace-visible and settable state. For internal state drivers
+ can subclass these structures through embeddeding, or add entirely new state
+ structures for their globally shared hardware functions.
+
+- An atomic update is assembled and validated as an entirely free-standing pile
+ of structures within the :c:type:`drm_atomic_state <drm_atomic_state>`
+ container. Again drivers can subclass that container for their own state
+ structure tracking needs. Only when a state is committed is it applied to the
+ driver and modeset objects. This way rolling back an update boils down to
+ releasing memory and unreferencing objects like framebuffers.
+
+Read on in this chapter, and also in :ref:`drm_atomic_helper` for more detailed
+coverage of specific topics.
+
+Atomic Mode Setting Function Reference
+--------------------------------------
.. kernel-doc:: include/drm/drm_atomic.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_atomic.c
+ :export:
+
CRTC Abstraction
================
@@ -68,12 +304,12 @@ Frame Buffer Abstraction
Frame Buffer Functions Reference
--------------------------------
-.. kernel-doc:: drivers/gpu/drm/drm_framebuffer.c
- :export:
-
.. kernel-doc:: include/drm/drm_framebuffer.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_framebuffer.c
+ :export:
+
DRM Format Handling
===================
@@ -376,8 +612,8 @@ operation handler.
Vertical Blanking and Interrupt Handling Functions Reference
------------------------------------------------------------
-.. kernel-doc:: drivers/gpu/drm/drm_irq.c
- :export:
-
.. kernel-doc:: include/drm/drm_irq.h
:internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_irq.c
+ :export:
diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
index f5760b140f13..96b9c34c21e4 100644
--- a/Documentation/gpu/drm-mm.rst
+++ b/Documentation/gpu/drm-mm.rst
@@ -183,14 +183,12 @@ GEM Objects Lifetime
--------------------
All GEM objects are reference-counted by the GEM core. References can be
-acquired and release by :c:func:`calling
-drm_gem_object_reference()` and
-:c:func:`drm_gem_object_unreference()` respectively. The caller
-must hold the :c:type:`struct drm_device <drm_device>`
-struct_mutex lock when calling
-:c:func:`drm_gem_object_reference()`. As a convenience, GEM
-provides :c:func:`drm_gem_object_unreference_unlocked()`
-functions that can be called without holding the lock.
+acquired and release by :c:func:`calling drm_gem_object_get()` and
+:c:func:`drm_gem_object_put()` respectively. The caller must hold the
+:c:type:`struct drm_device <drm_device>` struct_mutex lock when calling
+:c:func:`drm_gem_object_get()`. As a convenience, GEM provides
+:c:func:`drm_gem_object_put_unlocked()` functions that can be called without
+holding the lock.
When the last reference to a GEM object is released the GEM core calls
the :c:type:`struct drm_driver <drm_driver>` gem_free_object
@@ -367,36 +365,36 @@ from the client in libdrm.
GEM Function Reference
----------------------
-.. kernel-doc:: drivers/gpu/drm/drm_gem.c
- :export:
-
.. kernel-doc:: include/drm/drm_gem.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_gem.c
+ :export:
+
GEM CMA Helper Functions Reference
----------------------------------
.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c
:doc: cma helpers
-.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c
- :export:
-
.. kernel-doc:: include/drm/drm_gem_cma_helper.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c
+ :export:
+
VMA Offset Manager
==================
.. kernel-doc:: drivers/gpu/drm/drm_vma_manager.c
:doc: vma offset manager
-.. kernel-doc:: drivers/gpu/drm/drm_vma_manager.c
- :export:
-
.. kernel-doc:: include/drm/drm_vma_manager.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_vma_manager.c
+ :export:
+
PRIME Buffer Sharing
====================
@@ -451,6 +449,9 @@ PRIME Helper Functions
PRIME Function References
-------------------------
+.. kernel-doc:: include/drm/drm_prime.h
+ :internal:
+
.. kernel-doc:: drivers/gpu/drm/drm_prime.c
:export:
@@ -472,12 +473,12 @@ LRU Scan/Eviction Support
DRM MM Range Allocator Function References
------------------------------------------
-.. kernel-doc:: drivers/gpu/drm/drm_mm.c
- :export:
-
.. kernel-doc:: include/drm/drm_mm.h
:internal:
+.. kernel-doc:: drivers/gpu/drm/drm_mm.c
+ :export:
+
DRM Cache Handling
==================
diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
index fcc228ef5bc4..858457567d3d 100644
--- a/Documentation/gpu/drm-uapi.rst
+++ b/Documentation/gpu/drm-uapi.rst
@@ -21,6 +21,8 @@ libdrm Device Lookup
:doc: getunique and setversion story
+.. _drm_primary_node:
+
Primary Nodes, DRM Master and Authentication
============================================
@@ -103,6 +105,8 @@ is already rather painful for the DRM subsystem, with multiple different uAPIs
for the same thing co-existing. If we add a few more complete mistakes into the
mix every year it would be entirely unmanageable.
+.. _drm_render_node:
+
Render nodes
============
@@ -156,6 +160,20 @@ other hand, a driver requires shared state between clients which is
visible to user-space and accessible beyond open-file boundaries, they
cannot support render nodes.
+IOCTL Support on Device Nodes
+=============================
+
+.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
+ :doc: driver specific ioctls
+
+.. kernel-doc:: include/drm/drm_ioctl.h
+ :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
+ :export:
+
+.. kernel-doc:: drivers/gpu/drm/drm_ioc32.c
+ :export:
Testing and validation
======================
@@ -203,6 +221,28 @@ Display CRC Support
.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
:doc: CRC ABI
+.. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
+ :export:
+
+Debugfs Support
+---------------
+
+.. kernel-doc:: include/drm/drm_debugfs.h
+ :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_debugfs.c
+ :export:
+
+Sysfs Support
+=============
+
+.. kernel-doc:: drivers/gpu/drm/drm_sysfs.c
+ :doc: overview
+
+.. kernel-doc:: drivers/gpu/drm/drm_sysfs.c
+ :export:
+
+
VBlank event handling
=====================
diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst
index b0d6709b8600..9c7ed3e3f1e9 100644
--- a/Documentation/gpu/i915.rst
+++ b/Documentation/gpu/i915.rst
@@ -222,6 +222,15 @@ Video BIOS Table (VBT)
.. kernel-doc:: drivers/gpu/drm/i915/intel_vbt_defs.h
:internal:
+Display clocks
+--------------
+
+.. kernel-doc:: drivers/gpu/drm/i915/intel_cdclk.c
+ :doc: CDCLK / RAWCLK
+
+.. kernel-doc:: drivers/gpu/drm/i915/intel_cdclk.c
+ :internal:
+
Display PLLs
------------
diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst
index f81278a7c2cc..c572f092739e 100644
--- a/Documentation/gpu/index.rst
+++ b/Documentation/gpu/index.rst
@@ -11,9 +11,13 @@ Linux GPU Driver Developer's Guide
drm-kms-helpers
drm-uapi
i915
+ meson
tinydrm
+ vc4
vga-switcheroo
vgaarbiter
+ bridge/dw-hdmi
+ todo
.. only:: subproject and html
diff --git a/Documentation/gpu/introduction.rst b/Documentation/gpu/introduction.rst
index eb284eb748ba..fccbe375244d 100644
--- a/Documentation/gpu/introduction.rst
+++ b/Documentation/gpu/introduction.rst
@@ -50,3 +50,49 @@ names are "Notes" with information for dangerous or tricky corner cases,
and "FIXME" where the interface could be cleaned up.
Also read the :ref:`guidelines for the kernel documentation at large <doc_guide>`.
+
+Getting Started
+===============
+
+Developers interested in helping out with the DRM subsystem are very welcome.
+Often people will resort to sending in patches for various issues reported by
+checkpatch or sparse. We welcome such contributions.
+
+Anyone looking to kick it up a notch can find a list of janitorial tasks on
+the :ref:`TODO list <todo>`.
+
+Contribution Process
+====================
+
+Mostly the DRM subsystem works like any other kernel subsystem, see :ref:`the
+main process guidelines and documentation <process_index>` for how things work.
+Here we just document some of the specialities of the GPU subsystem.
+
+Feature Merge Deadlines
+-----------------------
+
+All feature work must be in the linux-next tree by the -rc6 release of the
+current release cycle, otherwise they must be postponed and can't reach the next
+merge window. All patches must have landed in the drm-next tree by latest -rc7,
+but if your branch is not in linux-next then this must have happened by -rc6
+already.
+
+After that point only bugfixes (like after the upstream merge window has closed
+with the -rc1 release) are allowed. No new platform enabling or new drivers are
+allowed.
+
+This means that there's a blackout-period of about one month where feature work
+can't be merged. The recommended way to deal with that is having a -next tree
+that's always open, but making sure to not feed it into linux-next during the
+blackout period. As an example, drm-misc works like that.
+
+Code of Conduct
+---------------
+
+As a freedesktop.org project, dri-devel, and the DRM community, follows the
+Contributor Covenant, found at: https://www.freedesktop.org/wiki/CodeOfConduct
+
+Please conduct yourself in a respectful and civilised manner when
+interacting with community members on mailing lists, IRC, or bug
+trackers. The community represents the project as a whole, and abusive
+or bullying behaviour is not tolerated by the project.
diff --git a/Documentation/gpu/kms-properties.csv b/Documentation/gpu/kms-properties.csv
index 981873a05d14..927b65e14219 100644
--- a/Documentation/gpu/kms-properties.csv
+++ b/Documentation/gpu/kms-properties.csv
@@ -1,10 +1,5 @@
Owner Module/Drivers,Group,Property Name,Type,Property Values,Object attached,Description/Restrictions
,,“scaling mode”,ENUM,"{ ""None"", ""Full"", ""Center"", ""Full aspect"" }",Connector,"Supported by: amdgpu, gma500, i915, nouveau and radeon."
-,Connector,“EDID”,BLOB | IMMUTABLE,0,Connector,Contains id of edid blob ptr object.
-,,“DPMS”,ENUM,"{ “On”, “Standby”, “Suspend”, “Off” }",Connector,Contains DPMS operation mode value.
-,,“PATH”,BLOB | IMMUTABLE,0,Connector,Contains topology path to a connector.
-,,“TILE”,BLOB | IMMUTABLE,0,Connector,Contains tiling information for a connector.
-,,“CRTC_ID”,OBJECT,DRM_MODE_OBJECT_CRTC,Connector,CRTC that connector is attached to (atomic)
,DVI-I,“subconnector”,ENUM,"{ “Unknown”, “DVI-D”, “DVI-A” }",Connector,TBD
,,“select subconnector”,ENUM,"{ “Automatic”, “DVI-D”, “DVI-A” }",Connector,TBD
,TV,“subconnector”,ENUM,"{ ""Unknown"", ""Composite"", ""SVIDEO"", ""Component"", ""SCART"" }",Connector,TBD
diff --git a/Documentation/gpu/meson.rst b/Documentation/gpu/meson.rst
new file mode 100644
index 000000000000..479f6f51a13b
--- /dev/null
+++ b/Documentation/gpu/meson.rst
@@ -0,0 +1,61 @@
+=============================================
+drm/meson AmLogic Meson Video Processing Unit
+=============================================
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_drv.c
+ :doc: Video Processing Unit
+
+Video Processing Unit
+=====================
+
+The Amlogic Meson Display controller is composed of several components
+that are going to be documented below:
+
+.. code::
+
+ DMC|---------------VPU (Video Processing Unit)----------------|------HHI------|
+ | vd1 _______ _____________ _________________ | |
+ D |-------| |----| | | | | HDMI PLL |
+ D | vd2 | VIU | | Video Post | | Video Encoders |<---|-----VCLK |
+ R |-------| |----| Processing | | | | |
+ | osd2 | | | |---| Enci ----------|----|-----VDAC------|
+ R |-------| CSC |----| Scalers | | Encp ----------|----|----HDMI-TX----|
+ A | osd1 | | | Blenders | | Encl ----------|----|---------------|
+ M |-------|______|----|____________| |________________| | |
+ ___|__________________________________________________________|_______________|
+
+Video Input Unit
+================
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_viu.c
+ :doc: Video Input Unit
+
+Video Post Processing
+=====================
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_vpp.c
+ :doc: Video Post Processing
+
+Video Encoder
+=============
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_venc.c
+ :doc: Video Encoder
+
+Video Canvas Management
+=======================
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_canvas.c
+ :doc: Canvas
+
+Video Clocks
+============
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_vclk.c
+ :doc: Video Clocks
+
+HDMI Video Output
+=================
+
+.. kernel-doc:: drivers/gpu/drm/meson/meson_dw_hdmi.c
+ :doc: HDMI Output
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
new file mode 100644
index 000000000000..1bdb7356a310
--- /dev/null
+++ b/Documentation/gpu/todo.rst
@@ -0,0 +1,407 @@
+.. _todo:
+
+=========
+TODO list
+=========
+
+This section contains a list of smaller janitorial tasks in the kernel DRM
+graphics subsystem useful as newbie projects. Or for slow rainy days.
+
+Subsystem-wide refactorings
+===========================
+
+De-midlayer drivers
+-------------------
+
+With the recent ``drm_bus`` cleanup patches for 3.17 it is no longer required
+to have a ``drm_bus`` structure set up. Drivers can directly set up the
+``drm_device`` structure instead of relying on bus methods in ``drm_usb.c``
+and ``drm_pci.c``. The goal is to get rid of the driver's ``->load`` /
+``->unload`` callbacks and open-code the load/unload sequence properly, using
+the new two-stage ``drm_device`` setup/teardown.
+
+Once all existing drivers are converted we can also remove those bus support
+files for USB and platform devices.
+
+All you need is a GPU for a non-converted driver (currently almost all of
+them, but also all the virtual ones used by KVM, so everyone qualifies).
+
+Contact: Daniel Vetter, Thierry Reding, respective driver maintainers
+
+Switch from reference/unreference to get/put
+--------------------------------------------
+
+For some reason DRM core uses ``reference``/``unreference`` suffixes for
+refcounting functions, but kernel uses ``get``/``put`` (e.g.
+``kref_get``/``put()``). It would be good to switch over for consistency, and
+it's shorter. Needs to be done in 3 steps for each pair of functions:
+
+* Create new ``get``/``put`` functions, define the old names as compatibility
+ wrappers
+* Switch over each file/driver using a cocci-generated spatch.
+* Once all users of the old names are gone, remove them.
+
+This way drivers/patches in the progress of getting merged won't break.
+
+Contact: Daniel Vetter
+
+Convert existing KMS drivers to atomic modesetting
+--------------------------------------------------
+
+3.19 has the atomic modeset interfaces and helpers, so drivers can now be
+converted over. Modern compositors like Wayland or Surfaceflinger on Android
+really want an atomic modeset interface, so this is all about the bright
+future.
+
+There is a conversion guide for atomic and all you need is a GPU for a
+non-converted driver (again virtual HW drivers for KVM are still all
+suitable).
+
+As part of this drivers also need to convert to universal plane (which means
+exposing primary & cursor as proper plane objects). But that's much easier to
+do by directly using the new atomic helper driver callbacks.
+
+Contact: Daniel Vetter, respective driver maintainers
+
+Clean up the clipped coordination confusion around planes
+---------------------------------------------------------
+
+We have a helper to get this right with drm_plane_helper_check_update(), but
+it's not consistently used. This should be fixed, preferrably in the atomic
+helpers (and drivers then moved over to clipped coordinates). Probably the
+helper should also be moved from drm_plane_helper.c to the atomic helpers, to
+avoid confusion - the other helpers in that file are all deprecated legacy
+helpers.
+
+Contact: Ville Syrjälä, Daniel Vetter, driver maintainers
+
+Implement deferred fbdev setup in the helper
+--------------------------------------------
+
+Many (especially embedded drivers) want to delay fbdev setup until there's a
+real screen plugged in. This is to avoid the dreaded fallback to the low-res
+fbdev default. Many drivers have a hacked-up (and often broken) version of this,
+better to do it once in the shared helpers. Thierry has a patch series, but that
+one needs to be rebased and final polish applied.
+
+Contact: Thierry Reding, Daniel Vetter, driver maintainers
+
+Convert early atomic drivers to async commit helpers
+----------------------------------------------------
+
+For the first year the atomic modeset helpers didn't support asynchronous /
+nonblocking commits, and every driver had to hand-roll them. This is fixed
+now, but there's still a pile of existing drivers that easily could be
+converted over to the new infrastructure.
+
+One issue with the helpers is that they require that drivers handle completion
+events for atomic commits correctly. But fixing these bugs is good anyway.
+
+Contact: Daniel Vetter, respective driver maintainers
+
+Better manual-upload support for atomic
+---------------------------------------
+
+This would be especially useful for tinydrm:
+
+- Add a struct drm_rect dirty_clip to drm_crtc_state. When duplicating the
+ crtc state, clear that to the max values, x/y = 0 and w/h = MAX_INT, in
+ __drm_atomic_helper_crtc_duplicate_state().
+
+- Move tinydrm_merge_clips into drm_framebuffer.c, dropping the tinydrm_
+ prefix ofc and using drm_fb_. drm_framebuffer.c makes sense since this
+ is a function useful to implement the fb->dirty function.
+
+- Create a new drm_fb_dirty function which does essentially what e.g.
+ mipi_dbi_fb_dirty does. You can use e.g. drm_atomic_helper_update_plane as the
+ template. But instead of doing a simple full-screen plane update, this new
+ helper also sets crtc_state->dirty_clip to the right coordinates. And of
+ course it needs to check whether the fb is actually active (and maybe where),
+ so there's some book-keeping involved. There's also some good fun involved in
+ scaling things appropriately. For that case we might simply give up and
+ declare the entire area covered by the plane as dirty.
+
+Contact: Noralf Trønnes, Daniel Vetter
+
+Fallout from atomic KMS
+-----------------------
+
+``drm_atomic_helper.c`` provides a batch of functions which implement legacy
+IOCTLs on top of the new atomic driver interface. Which is really nice for
+gradual conversion of drivers, but unfortunately the semantic mismatches are
+a bit too severe. So there's some follow-up work to adjust the function
+interfaces to fix these issues:
+
+* atomic needs the lock acquire context. At the moment that's passed around
+ implicitly with some horrible hacks, and it's also allocate with
+ ``GFP_NOFAIL`` behind the scenes. All legacy paths need to start allocating
+ the acquire context explicitly on stack and then also pass it down into
+ drivers explicitly so that the legacy-on-atomic functions can use them.
+
+* A bunch of the vtable hooks are now in the wrong place: DRM has a split
+ between core vfunc tables (named ``drm_foo_funcs``), which are used to
+ implement the userspace ABI. And then there's the optional hooks for the
+ helper libraries (name ``drm_foo_helper_funcs``), which are purely for
+ internal use. Some of these hooks should be move from ``_funcs`` to
+ ``_helper_funcs`` since they are not part of the core ABI. There's a
+ ``FIXME`` comment in the kerneldoc for each such case in ``drm_crtc.h``.
+
+* There's a new helper ``drm_atomic_helper_best_encoder()`` which could be
+ used by all atomic drivers which don't select the encoder for a given
+ connector at runtime. That's almost all of them, and would allow us to get
+ rid of a lot of ``best_encoder`` boilerplate in drivers.
+
+Contact: Daniel Vetter
+
+Get rid of dev->struct_mutex from GEM drivers
+---------------------------------------------
+
+``dev->struct_mutex`` is the Big DRM Lock from legacy days and infested
+everything. Nowadays in modern drivers the only bit where it's mandatory is
+serializing GEM buffer object destruction. Which unfortunately means drivers
+have to keep track of that lock and either call ``unreference`` or
+``unreference_locked`` depending upon context.
+
+Core GEM doesn't have a need for ``struct_mutex`` any more since kernel 4.8,
+and there's a ``gem_free_object_unlocked`` callback for any drivers which are
+entirely ``struct_mutex`` free.
+
+For drivers that need ``struct_mutex`` it should be replaced with a driver-
+private lock. The tricky part is the BO free functions, since those can't
+reliably take that lock any more. Instead state needs to be protected with
+suitable subordinate locks or some cleanup work pushed to a worker thread. For
+performance-critical drivers it might also be better to go with a more
+fine-grained per-buffer object and per-context lockings scheme. Currently the
+following drivers still use ``struct_mutex``: ``msm``, ``omapdrm`` and
+``udl``.
+
+Contact: Daniel Vetter, respective driver maintainers
+
+Switch to drm_connector_list_iter for any connector_list walking
+----------------------------------------------------------------
+
+Connectors can be hotplugged, and we now have a special list of helpers to walk
+the connector_list in a race-free fashion, without incurring deadlocks on
+mutexes and other fun stuff.
+
+Unfortunately most drivers are not converted yet. At least all those supporting
+DP MST hotplug should be converted, since for those drivers the difference
+matters. See drm_for_each_connector_iter() vs. drm_for_each_connector().
+
+Contact: Daniel Vetter
+
+Core refactorings
+=================
+
+Use new IDR deletion interface to clean up drm_gem_handle_delete()
+------------------------------------------------------------------
+
+See the "This is gross" comment -- apparently the IDR system now can return an
+error code instead of oopsing.
+
+Clean up the DRM header mess
+----------------------------
+
+Currently the DRM subsystem has only one global header, ``drmP.h``. This is
+used both for functions exported to helper libraries and drivers and functions
+only used internally in the ``drm.ko`` module. The goal would be to move all
+header declarations not needed outside of ``drm.ko`` into
+``drivers/gpu/drm/drm_*_internal.h`` header files. ``EXPORT_SYMBOL`` also
+needs to be dropped for these functions.
+
+This would nicely tie in with the below task to create kerneldoc after the API
+is cleaned up. Or with the "hide legacy cruft better" task.
+
+Note that this is well in progress, but ``drmP.h`` is still huge. The updated
+plan is to switch to per-file driver API headers, which will also structure
+the kerneldoc better. This should also allow more fine-grained ``#include``
+directives.
+
+In the end no .c file should need to include ``drmP.h`` anymore.
+
+Contact: Daniel Vetter
+
+Add missing kerneldoc for exported functions
+--------------------------------------------
+
+The DRM reference documentation is still lacking kerneldoc in a few areas. The
+task would be to clean up interfaces like moving functions around between
+files to better group them and improving the interfaces like dropping return
+values for functions that never fail. Then write kerneldoc for all exported
+functions and an overview section and integrate it all into the drm DocBook.
+
+See https://dri.freedesktop.org/docs/drm/ for what's there already.
+
+Contact: Daniel Vetter
+
+Hide legacy cruft better
+------------------------
+
+Way back DRM supported only drivers which shadow-attached to PCI devices with
+userspace or fbdev drivers setting up outputs. Modern DRM drivers take charge
+of the entire device, you can spot them with the DRIVER_MODESET flag.
+
+Unfortunately there's still large piles of legacy code around which needs to
+be hidden so that driver writers don't accidentally end up using it. And to
+prevent security issues in those legacy IOCTLs from being exploited on modern
+drivers. This has multiple possible subtasks:
+
+* Extract support code for legacy features into a ``drm-legacy.ko`` kernel
+ module and compile it only when one of the legacy drivers is enabled.
+
+This is mostly done, the only thing left is to split up ``drm_irq.c`` into
+legacy cruft and the parts needed by modern KMS drivers.
+
+Contact: Daniel Vetter
+
+Make panic handling work
+------------------------
+
+This is a really varied tasks with lots of little bits and pieces:
+
+* The panic path can't be tested currently, leading to constant breaking. The
+ main issue here is that panics can be triggered from hardirq contexts and
+ hence all panic related callback can run in hardirq context. It would be
+ awesome if we could test at least the fbdev helper code and driver code by
+ e.g. trigger calls through drm debugfs files. hardirq context could be
+ achieved by using an IPI to the local processor.
+
+* There's a massive confusion of different panic handlers. DRM fbdev emulation
+ helpers have one, but on top of that the fbcon code itself also has one. We
+ need to make sure that they stop fighting over each another.
+
+* ``drm_can_sleep()`` is a mess. It hides real bugs in normal operations and
+ isn't a full solution for panic paths. We need to make sure that it only
+ returns true if there's a panic going on for real, and fix up all the
+ fallout.
+
+* The panic handler must never sleep, which also means it can't ever
+ ``mutex_lock()``. Also it can't grab any other lock unconditionally, not
+ even spinlocks (because NMI and hardirq can panic too). We need to either
+ make sure to not call such paths, or trylock everything. Really tricky.
+
+* For the above locking troubles reasons it's pretty much impossible to
+ attempt a synchronous modeset from panic handlers. The only thing we could
+ try to achive is an atomic ``set_base`` of the primary plane, and hope that
+ it shows up. Everything else probably needs to be delayed to some worker or
+ something else which happens later on. Otherwise it just kills the box
+ harder, prevent the panic from going out on e.g. netconsole.
+
+* There's also proposal for a simplied DRM console instead of the full-blown
+ fbcon and DRM fbdev emulation. Any kind of panic handling tricks should
+ obviously work for both console, in case we ever get kmslog merged.
+
+Contact: Daniel Vetter
+
+Clean up the debugfs support
+----------------------------
+
+There's a bunch of issues with it:
+
+- The drm_info_list ->show() function doesn't even bother to cast to the drm
+ structure for you. This is lazy.
+
+- We probably want to have some support for debugfs files on crtc/connectors and
+ maybe other kms objects directly in core. There's even drm_print support in
+ the funcs for these objects to dump kms state, so it's all there. And then the
+ ->show() functions should obviously give you a pointer to the right object.
+
+- The drm_info_list stuff is centered on drm_minor instead of drm_device. For
+ anything we want to print drm_device (or maybe drm_file) is the right thing.
+
+- The drm_driver->debugfs_init hooks we have is just an artifact of the old
+ midlayered load sequence. DRM debugfs should work more like sysfs, where you
+ can create properties/files for an object anytime you want, and the core
+ takes care of publishing/unpuplishing all the files at register/unregister
+ time. Drivers shouldn't need to worry about these technicalities, and fixing
+ this (together with the drm_minor->drm_device move) would allow us to remove
+ debugfs_init.
+
+Contact: Daniel Vetter
+
+Better Testing
+==============
+
+Enable trinity for DRM
+----------------------
+
+And fix up the fallout. Should be really interesting ...
+
+Make KMS tests in i-g-t generic
+-------------------------------
+
+The i915 driver team maintains an extensive testsuite for the i915 DRM driver,
+including tons of testcases for corner-cases in the modesetting API. It would
+be awesome if those tests (at least the ones not relying on Intel-specific GEM
+features) could be made to run on any KMS driver.
+
+Basic work to run i-g-t tests on non-i915 is done, what's now missing is mass-
+converting things over. For modeset tests we also first need a bit of
+infrastructure to use dumb buffers for untiled buffers, to be able to run all
+the non-i915 specific modeset tests.
+
+Contact: Daniel Vetter
+
+Create a virtual KMS driver for testing (vkms)
+----------------------------------------------
+
+With all the latest helpers it should be fairly simple to create a virtual KMS
+driver useful for testing, or for running X or similar on headless machines
+(to be able to still use the GPU). This would be similar to vgem, but aimed at
+the modeset side.
+
+Once the basics are there there's tons of possibilities to extend it.
+
+Contact: Daniel Vetter
+
+Driver Specific
+===============
+
+tinydrm
+-------
+
+Tinydrm is the helper driver for really simple fb drivers. The goal is to make
+those drivers as simple as possible, so lots of room for refactoring:
+
+- backlight helpers, probably best to put them into a new drm_backlight.c.
+ This is because drivers/video is de-facto unmaintained. We could also
+ move drivers/video/backlight to drivers/gpu/backlight and take it all
+ over within drm-misc, but that's more work.
+
+- spi helpers, probably best put into spi core/helper code. Thierry said
+ the spi maintainer is fast&reactive, so shouldn't be a big issue.
+
+- extract the mipi-dbi helper (well, the non-tinydrm specific parts at
+ least) into a separate helper, like we have for mipi-dsi already. Or follow
+ one of the ideas for having a shared dsi/dbi helper, abstracting away the
+ transport details more.
+
+- tinydrm_lastclose could be drm_fb_helper_lastclose. Only thing we need
+ for that is to store the drm_fb_helper pointer somewhere in
+ drm_device->mode_config. And then we could roll that out to all the
+ drivers.
+
+- tinydrm_gem_cma_prime_import_sg_table should probably go into the cma
+ helpers, as a _vmapped variant (since not every driver needs the vmap).
+ And tinydrm_gem_cma_free_object could the be merged into
+ drm_gem_cma_free_object().
+
+- tinydrm_fb_create we could move into drm_simple_pipe, only need to add
+ the fb_create hook to drm_simple_pipe_funcs, which would again simplify a
+ bunch of things (since it gives you a one-stop vfunc for simple drivers).
+
+- Quick aside: The unregister devm stuff is kinda getting the lifetimes of
+ a drm_device wrong. Doesn't matter, since everyone else gets it wrong
+ too :-)
+
+- With the fbdev pointer in dev->mode_config we could also make
+ suspend/resume helpers entirely generic, at least if we add a
+ dev->mode_config.suspend_state. We could even provide a generic pm_ops
+ structure with those.
+
+- also rework the drm_framebuffer_funcs->dirty hook wire-up, see above.
+
+Contact: Noralf Trønnes, Daniel Vetter
+
+Outside DRM
+===========
diff --git a/Documentation/gpu/vc4.rst b/Documentation/gpu/vc4.rst
new file mode 100644
index 000000000000..5df1d98b9544
--- /dev/null
+++ b/Documentation/gpu/vc4.rst
@@ -0,0 +1,89 @@
+=====================================
+ drm/vc4 Broadcom VC4 Graphics Driver
+=====================================
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_drv.c
+ :doc: Broadcom VC4 Graphics Driver
+
+Display Hardware Handling
+=========================
+
+This section covers everything related to the display hardware including
+the mode setting infrastructure, plane, sprite and cursor handling and
+display, output probing and related topics.
+
+Pixel Valve (DRM CRTC)
+----------------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_crtc.c
+ :doc: VC4 CRTC module
+
+HVS
+---
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_hvs.c
+ :doc: VC4 HVS module.
+
+HVS planes
+----------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_plane.c
+ :doc: VC4 plane module
+
+HDMI encoder
+------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_hdmi.c
+ :doc: VC4 Falcon HDMI module
+
+DSI encoder
+-----------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_dsi.c
+ :doc: VC4 DSI0/DSI1 module
+
+DPI encoder
+-----------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_dpi.c
+ :doc: VC4 DPI module
+
+VEC (Composite TV out) encoder
+------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_vec.c
+ :doc: VC4 SDTV module
+
+Memory Management and 3D Command Submission
+===========================================
+
+This section covers the GEM implementation in the vc4 driver.
+
+GPU buffer object (BO) management
+---------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_bo.c
+ :doc: VC4 GEM BO management support
+
+V3D binner command list (BCL) validation
+----------------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_validate.c
+ :doc: Command list validator for VC4.
+
+V3D render command list (RCL) generation
+----------------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_render_cl.c
+ :doc: Render command list generation
+
+Shader validator for VC4
+---------------------------
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_validate_shaders.c
+ :doc: Shader validator for VC4.
+
+V3D Interrupts
+--------------
+
+.. kernel-doc:: drivers/gpu/drm/vc4/vc4_irq.c
+ :doc: Interrupt management for the V3D engine