drm/doc: Drop chapter "KMS Initialization and Cleanup"

danvet · danvet · commit d9f7bb56c292 · 2019-01-30T22:16:18.000+01:00
It only talks about crtc, brings up intel as an example and I think is more misleading than useful really. Plus we have lots of discussion about how your standard kms driver should be initialized/cleaned up, so maybe better to document this when we have a better idea. v2: Fix typo in commit message (Nicholas). Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190130163006.28945-2-daniel.vetter@ffwll.ch
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
@@ -410,102 +410,6 @@ Encoder Functions Reference
 .. kernel-doc:: drivers/gpu/drm/drm_encoder.c
    :export:
 
-KMS Initialization and Cleanup
-==============================
-
-A KMS device is abstracted and exposed as a set of planes, CRTCs,
-encoders and connectors. KMS drivers must thus create and initialize all
-those objects at load time after initializing mode setting.
-
-CRTCs (:c:type:`struct drm_crtc <drm_crtc>`)
---------------------------------------------
-
-A CRTC is an abstraction representing a part of the chip that contains a
-pointer to a scanout buffer. Therefore, the number of CRTCs available
-determines how many independent scanout buffers can be active at any
-given time. The CRTC structure contains several fields to support this:
-a pointer to some video memory (abstracted as a frame buffer object), a
-display mode, and an (x, y) offset into the video memory to support
-panning or configurations where one piece of video memory spans multiple
-CRTCs.
-
-CRTC Initialization
-~~~~~~~~~~~~~~~~~~~
-
-A KMS device must create and register at least one struct
-:c:type:`struct drm_crtc <drm_crtc>` instance. The instance is
-allocated and zeroed by the driver, possibly as part of a larger
-structure, and registered with a call to :c:func:`drm_crtc_init()`
-with a pointer to CRTC functions.
-
-
-Cleanup
--------
-
-The DRM core manages its objects' lifetime. When an object is not needed
-anymore the core calls its destroy function, which must clean up and
-free every resource allocated for the object. Every
-:c:func:`drm_\*_init()` call must be matched with a corresponding
-:c:func:`drm_\*_cleanup()` call to cleanup CRTCs
-(:c:func:`drm_crtc_cleanup()`), planes
-(:c:func:`drm_plane_cleanup()`), encoders
-(:c:func:`drm_encoder_cleanup()`) and connectors
-(:c:func:`drm_connector_cleanup()`). Furthermore, connectors that
-have been added to sysfs must be removed by a call to
-:c:func:`drm_connector_unregister()` before calling
-:c:func:`drm_connector_cleanup()`.
-
-Connectors state change detection must be cleanup up with a call to
-:c:func:`drm_kms_helper_poll_fini()`.
-
-Output discovery and initialization example
--------------------------------------------
-
-.. code-block:: c
-
-    void intel_crt_init(struct drm_device *dev)
-    {
-        struct drm_connector *connector;
-        struct intel_output *intel_output;
-
-        intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL);
-        if (!intel_output)
-            return;
-
-        connector = &intel_output->base;
-        drm_connector_init(dev, &intel_output->base,
-                   &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA);
-
-        drm_encoder_init(dev, &intel_output->enc, &intel_crt_enc_funcs,
-                 DRM_MODE_ENCODER_DAC);
-
-        drm_connector_attach_encoder(&intel_output->base,
-                          &intel_output->enc);
-
-        /* Set up the DDC bus. */
-        intel_output->ddc_bus = intel_i2c_create(dev, GPIOA, "CRTDDC_A");
-        if (!intel_output->ddc_bus) {
-            dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration "
-                   "failed.\n");
-            return;
-        }
-
-        intel_output->type = INTEL_OUTPUT_ANALOG;
-        connector->interlace_allowed = 0;
-        connector->doublescan_allowed = 0;
-
-        drm_encoder_helper_add(&intel_output->enc, &intel_crt_helper_funcs);
-        drm_connector_helper_add(connector, &intel_crt_connector_helper_funcs);
-
-        drm_connector_register(connector);
-    }
-
-In the example above (taken from the i915 driver), a CRTC, connector and
-encoder combination is created. A device-specific i2c bus is also
-created for fetching EDID data and performing monitor detection. Once
-the process is complete, the new connector is registered with sysfs to
-make its properties available to applications.
-
 KMS Locking
 ===========
 
