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path: root/test/object.cpp

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
 *
 * delayed_controls.h - Helper to deal with controls that take effect with a delay
 */

#include "libcamera/internal/delayed_controls.h"

#include <libcamera/base/log.h>

#include <libcamera/controls.h>

#include "libcamera/internal/v4l2_device.h"

/**
 * \file delayed_controls.h
 * \brief Helper to deal with controls that take effect with a delay
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(DelayedControls)

/**
 * \class DelayedControls
 * \brief Helper to deal with controls that take effect with a delay
 *
 * Some sensor controls take effect with a delay as the sensor needs time to
 * adjust, for example exposure and analog gain. This is a helper class to deal
 * with such controls and the intended users are pipeline handlers.
 *
 * The idea is to extend the concept of the buffer depth of a pipeline the
 * application needs to maintain to also cover controls. Just as with buffer
 * depth if the application keeps the number of requests queued above the
 * control depth the controls are guaranteed to take effect for the correct
 * request. The control depth is determined by the control with the greatest
 * delay.
 */

/**
 * \struct DelayedControls::ControlParams
 * \brief Parameters associated with controls handled by the \a DelayedControls
 * helper class
 *
 * \var ControlParams::delay
 * \brief Frame delay from setting the control on a sensor device to when it is
 * consumed during framing.
 *
 * \var ControlParams::priorityWrite
 * \brief Flag to indicate that this control must be applied ahead of, and
 * separately from the other controls.
 *
 * Typically set for the \a V4L2_CID_VBLANK control so that the device driver
 * does not reject \a V4L2_CID_EXPOSURE control values that may be outside of
 * the existing vertical blanking specified bounds, but are within the new
 * blanking bounds.
 */

/**
 * \brief Construct a DelayedControls instance
 * \param[in] device The V4L2 device the controls have to be applied to
 * \param[in] controlParams Map of the numerical V4L2 control ids to their
 * associated control parameters.
 *
 * The control parameters comprise of delays (in frames) and a priority write
 * flag. If this flag is set, the relevant control is written separately from,
 * and ahead of the rest of the batched controls.
 *
 * Only controls specified in \a controlParams are handled. If it's desired to
 * mix delayed controls and controls that take effect immediately the immediate
 * controls must be listed in the \a controlParams map with a delay value of 0.
 */
DelayedControls::DelayedControls(V4L2Device *device,
				 const std::unordered_map<uint32_t, ControlParams> &controlParams)
	: device_(device), maxDelay_(0)
{
	const ControlInfoMap &controls = device_->controls();

	/*
	 * Create a map of control ids to delays for controls exposed by the
	 * device.
	 */
	for (auto const &param : controlParams) {
		auto it = controls.find(param.first);
		if (it == controls.end()) {
			LOG(DelayedControls, Error)
				<< "Delay request for control id "
				<< utils::hex(param.first)
				<< " but control is not exposed by device "
				<< device_->deviceNode();