linux/drivers/gpu/drm/drm_crtc_helper.c

/*
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <[email protected]>
 *
 * DRM core CRTC related functions
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 *
 * Authors:
 *      Keith Packard
 *	Eric Anholt <[email protected]>
 *      Dave Airlie <[email protected]>
 *      Jesse Barnes <[email protected]>
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/dynamic_debug.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_atomic_uapi.h>
#include <drm/drm_bridge.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>

#include "drm_crtc_helper_internal.h"

DECLARE_DYNDBG_CLASSMAP();

/**
 * DOC: overview
 *
 * The CRTC modeset helper library provides a default set_config implementation
 * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
 * the same callbacks which drivers can use to e.g. restore the modeset
 * configuration on resume with drm_helper_resume_force_mode().
 *
 * Note that this helper library doesn't track the current power state of CRTCs
 * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
 * though the hardware is already in the desired state. This deficiency has been
 * fixed in the atomic helpers.
 *
 * The driver callbacks are mostly compatible with the atomic modeset helpers,
 * except for the handling of the primary plane: Atomic helpers require that the
 * primary plane is implemented as a real standalone plane and not directly tied
 * to the CRTC state. For easier transition this library provides functions to
 * implement the old semantics required by the CRTC helpers using the new plane
 * and atomic helper callbacks.
 *
 * Drivers are strongly urged to convert to the atomic helpers (by way of first
 * converting to the plane helpers). New drivers must not use these functions
 * but need to implement the atomic interface instead, potentially using the
 * atomic helpers for that.
 *
 * These legacy modeset helpers use the same function table structures as
 * all other modesetting helpers. See the documentation for struct
 * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
 * &drm_connector_helper_funcs.
 */

/**
 * drm_helper_encoder_in_use - check if a given encoder is in use
 * @encoder: encoder to check
 *
 * Checks whether @encoder is with the current mode setting output configuration
 * in use by any connector. This doesn't mean that it is actually enabled since
 * the DPMS state is tracked separately.
 *
 * Returns:
 * True if @encoder is used, false otherwise.
 */
bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
{}
EXPORT_SYMBOL();

/**
 * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 * @crtc: CRTC to check
 *
 * Checks whether @crtc is with the current mode setting output configuration
 * in use by any connector. This doesn't mean that it is actually enabled since
 * the DPMS state is tracked separately.
 *
 * Returns:
 * True if @crtc is used, false otherwise.
 */
bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
{}
EXPORT_SYMBOL();

static void
drm_encoder_disable(struct drm_encoder *encoder)
{}

static void __drm_helper_disable_unused_functions(struct drm_device *dev)
{}

/**
 * drm_helper_disable_unused_functions - disable unused objects
 * @dev: DRM device
 *
 * This function walks through the entire mode setting configuration of @dev. It
 * will remove any CRTC links of unused encoders and encoder links of
 * disconnected connectors. Then it will disable all unused encoders and CRTCs
 * either by calling their disable callback if available or by calling their
 * dpms callback with DRM_MODE_DPMS_OFF.
 *
 * NOTE:
 *
 * This function is part of the legacy modeset helper library and will cause
 * major confusion with atomic drivers. This is because atomic helpers guarantee
 * to never call ->disable() hooks on a disabled function, or ->enable() hooks
 * on an enabled functions. drm_helper_disable_unused_functions() on the other
 * hand throws such guarantees into the wind and calls disable hooks
 * unconditionally on unused functions.
 */
void drm_helper_disable_unused_functions(struct drm_device *dev)
{}
EXPORT_SYMBOL();

/*
 * Check the CRTC we're going to map each output to vs. its current
 * CRTC.  If they don't match, we have to disable the output and the CRTC
 * since the driver will have to re-route things.
 */
static void
drm_crtc_prepare_encoders(struct drm_device *dev)
{}

/**
 * drm_crtc_helper_set_mode - internal helper to set a mode
 * @crtc: CRTC to program
 * @mode: mode to use
 * @x: horizontal offset into the surface
 * @y: vertical offset into the surface
 * @old_fb: old framebuffer, for cleanup
 *
 * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
 * to fixup or reject the mode prior to trying to set it. This is an internal
 * helper that drivers could e.g. use to update properties that require the
 * entire output pipe to be disabled and re-enabled in a new configuration. For
 * example for changing whether audio is enabled on a hdmi link or for changing
 * panel fitter or dither attributes. It is also called by the
 * drm_crtc_helper_set_config() helper function to drive the mode setting
 * sequence.
 *
 * Returns:
 * True if the mode was set successfully, false otherwise.
 */
bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
			      struct drm_display_mode *mode,
			      int x, int y,
			      struct drm_framebuffer *old_fb)
{}
EXPORT_SYMBOL();

/**
 * drm_crtc_helper_atomic_check() - Helper to check CRTC atomic-state
 * @crtc: CRTC to check
 * @state: atomic state object
 *
 * Provides a default CRTC-state check handler for CRTCs that only have
 * one primary plane attached to it. This is often the case for the CRTC
 * of simple framebuffers.
 *
 * RETURNS:
 * Zero on success, or an errno code otherwise.
 */
int drm_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
{}
EXPORT_SYMBOL();

static void
drm_crtc_helper_disable(struct drm_crtc *crtc)
{}

/*
 * For connectors that support multiple encoders, either the
 * .atomic_best_encoder() or .best_encoder() operation must be implemented.
 */
struct drm_encoder *
drm_connector_get_single_encoder(struct drm_connector *connector)
{}

/**
 * drm_crtc_helper_set_config - set a new config from userspace
 * @set: mode set configuration
 * @ctx: lock acquire context, not used here
 *
 * The drm_crtc_helper_set_config() helper function implements the of
 * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
 * helpers.
 *
 * It first tries to locate the best encoder for each connector by calling the
 * connector @drm_connector_helper_funcs.best_encoder helper operation.
 *
 * After locating the appropriate encoders, the helper function will call the
 * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
 * or reject it completely in which case an error will be returned to the
 * application. If the new configuration after mode adjustment is identical to
 * the current configuration the helper function will return without performing
 * any other operation.
 *
 * If the adjusted mode is identical to the current mode but changes to the
 * frame buffer need to be applied, the drm_crtc_helper_set_config() function
 * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
 *
 * If the adjusted mode differs from the current mode, or if the
 * ->mode_set_base() helper operation is not provided, the helper function
 * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
 * and ->commit() CRTC and encoder helper operations, in that order.
 * Alternatively it can also use the dpms and disable helper operations. For
 * details see &struct drm_crtc_helper_funcs and struct
 * &drm_encoder_helper_funcs.
 *
 * This function is deprecated.  New drivers must implement atomic modeset
 * support, for which this function is unsuitable. Instead drivers should use
 * drm_atomic_helper_set_config().
 *
 * Returns:
 * Returns 0 on success, negative errno numbers on failure.
 */
int drm_crtc_helper_set_config(struct drm_mode_set *set,
			       struct drm_modeset_acquire_ctx *ctx)
{}
EXPORT_SYMBOL();

static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
{}

/* Helper which handles bridge ordering around encoder dpms */
static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
{}

static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
{}

/**
 * drm_helper_connector_dpms() - connector dpms helper implementation
 * @connector: affected connector
 * @mode: DPMS mode
 *
 * The drm_helper_connector_dpms() helper function implements the
 * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
 * helpers.
 *
 * This is the main helper function provided by the CRTC helper framework for
 * implementing the DPMS connector attribute. It computes the new desired DPMS
 * state for all encoders and CRTCs in the output mesh and calls the
 * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
 * provided by the driver.
 *
 * This function is deprecated.  New drivers must implement atomic modeset
 * support, where DPMS is handled in the DRM core.
 *
 * Returns:
 * Always returns 0.
 */
int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
{}
EXPORT_SYMBOL();

/**
 * drm_helper_resume_force_mode - force-restore mode setting configuration
 * @dev: drm_device which should be restored
 *
 * Drivers which use the mode setting helpers can use this function to
 * force-restore the mode setting configuration e.g. on resume or when something
 * else might have trampled over the hw state (like some overzealous old BIOSen
 * tended to do).
 *
 * This helper doesn't provide a error return value since restoring the old
 * config should never fail due to resource allocation issues since the driver
 * has successfully set the restored configuration already. Hence this should
 * boil down to the equivalent of a few dpms on calls, which also don't provide
 * an error code.
 *
 * Drivers where simply restoring an old configuration again might fail (e.g.
 * due to slight differences in allocating shared resources when the
 * configuration is restored in a different order than when userspace set it up)
 * need to use their own restore logic.
 *
 * This function is deprecated. New drivers should implement atomic mode-
 * setting and use the atomic suspend/resume helpers.
 *
 * See also:
 * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
 */
void drm_helper_resume_force_mode(struct drm_device *dev)
{}
EXPORT_SYMBOL();

/**
 * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
 * @dev: DRM device whose CRTCs to turn off
 *
 * Drivers may want to call this on unload to ensure that all displays are
 * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
 *
 * Note: This should only be used by non-atomic legacy drivers. For an atomic
 * version look at drm_atomic_helper_shutdown().
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_helper_force_disable_all(struct drm_device *dev)
{}
EXPORT_SYMBOL();