linux-imx

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Mode Setting Helper Functions

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The DRM subsystem aims for a strong separation between core code and helper

libraries. Core code takes care of general setup and teardown and decoding

userspace requests to kernel internal objects. Everything else is handled by a

large set of helper libraries, which can be combined freely to pick and choose

for each driver what fits, and avoid shared code where special behaviour is

needed.

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This distinction between core code and helpers is especially strong in the

modesetting code, where there's a shared userspace ABI for all drivers. This is

in contrast to the render side, where pretty much everything (with very few

exceptions) can be considered optional helper code.

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There are a few areas these helpers can grouped into:

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* Helpers to implement modesetting. The important ones here are the atomic

  helpers. Old drivers still often use the legacy CRTC helpers. They both share

  the same set of common helper vtables. For really simple drivers (anything

  that would have been a great fit in the deprecated fbdev subsystem) there's

  also the simple display pipe helpers.

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* There's a big pile of helpers for handling outputs. First the generic bridge

  helpers for handling encoder and transcoder IP blocks. Second the panel helpers

  for handling panel-related information and logic. Plus then a big set of

  helpers for the various sink standards (DisplayPort, HDMI, MIPI DSI). Finally

  there's also generic helpers for handling output probing, and for dealing with

  EDIDs.

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* The last group of helpers concerns itself with the frontend side of a display

  pipeline: Planes, handling rectangles for visibility checking and scissoring,

  flip queues and assorted bits.

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Modeset Helper Reference for Common Vtables

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.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h

   :doc: overview

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.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h

   :internal:

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.. _drm_atomic_helper:

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Atomic Modeset Helper Functions Reference

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Overview

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.. kernel-doc:: drivers/gpu/drm/drm_atomic_helper.c

   :doc: overview

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Implementing Asynchronous Atomic Commit

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.. kernel-doc:: drivers/gpu/drm/drm_atomic_helper.c

   :doc: implementing nonblocking commit

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Helper Functions Reference

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