Introduce colord integration

This change introduces basic colord integration in wayland session. It
is implemented as a binary plugin.

If an output is connected, the plugin will create the corresponding
colord device using the D-Bus API and start monitoring the device for
changes.

When a colord devices changes, the plugin will read the VCGT tag of the
current ICC color profile and apply it.

CMakeLists.txt

@@ -236,6 +236,14 @@ set_package_properties(X11 PROPERTIES
 add_feature_info("XInput" X11_Xinput_FOUND "Required for poll-free mouse cursor updates")
 set(HAVE_X11_XINPUT ${X11_Xinput_FOUND})
 
+find_package(lcms2)
+set_package_properties(lcms2 PROPERTIES
+    DESCRIPTION "Small-footprint color management engine"
+    URL "http://www.littlecms.com"
+    TYPE OPTIONAL
+)
+set(HAVE_LCMS2 ${lcms2_FOUND})
+
 # All the required XCB components
 find_package(XCB 1.10 REQUIRED COMPONENTS
     COMPOSITE

cmake/modules/Findlcms2.cmake

@@ -0,0 +1,95 @@
+#.rst:
+# Findlcms2
+# -------
+#
+# Try to find lcms2 on a Unix system.
+#
+# This will define the following variables:
+#
+# ``lcms2_FOUND``
+#     True if (the requested version of) lcms2 is available
+# ``lcms2_VERSION``
+#     The version of lcms2
+# ``lcms2_LIBRARIES``
+#     This should be passed to target_compile_options() if the target is not
+#     used for linking
+# ``lcms2_INCLUDE_DIRS``
+#     This should be passed to target_include_directories() if the target is not
+#     used for linking
+# ``lcms2_DEFINITIONS``
+#     This should be passed to target_compile_options() if the target is not
+#     used for linking
+#
+# If ``lcms2_FOUND`` is TRUE, it will also define the following imported target:
+#
+# ``lcms2::lcms2``
+#     The lcms2 library
+#
+# In general we recommend using the imported target, as it is easier to use.
+# Bear in mind, however, that if the target is in the link interface of an
+# exported library, it must be made available by the package config file.
+
+# Copyright (C) 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. Neither the name of the University nor the names of its contributors
+#    may be used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+find_package(PkgConfig)
+pkg_check_modules(PKG_lcms2 QUIET lcms2)
+
+set(lcms2_VERSION ${PKG_lcms2_VERSION})
+set(lcms2_DEFINITIONS ${PKG_lcms2_CFLAGS_OTHER})
+
+find_path(lcms2_INCLUDE_DIR
+    NAMES lcms2.h
+    HINTS ${PKG_lcms2_INCLUDE_DIRS}
+)
+
+find_library(lcms2_LIBRARY
+    NAMES lcms2
+    HINTS ${PKG_lcms2_LIBRARY_DIRS}
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(lcms2
+    FOUND_VAR lcms2_FOUND
+    REQUIRED_VARS lcms2_LIBRARY
+                  lcms2_INCLUDE_DIR
+    VERSION_VAR lcms2_VERSION
+)
+
+if (lcms2_FOUND AND NOT TARGET lcms2::lcms2)
+    add_library(lcms2::lcms2 UNKNOWN IMPORTED)
+    set_target_properties(lcms2::lcms2 PROPERTIES
+        IMPORTED_LOCATION "${lcms2_LIBRARY}"
+        INTERFACE_COMPILE_OPTIONS "${lcms2_DEFINITIONS}"
+        INTERFACE_INCLUDE_DIRECTORIES "${lcms2_INCLUDE_DIR}"
+    )
+endif()
+
+set(lcms2_INCLUDE_DIRS ${lcms2_INCLUDE_DIR})
+set(lcms2_LIBRARIES ${lcms2_LIBRARY})
+
+mark_as_advanced(lcms2_INCLUDE_DIR)
+mark_as_advanced(lcms2_LIBRARY)

config-kwin.h.cmake

@@ -30,6 +30,7 @@
 #cmakedefine01 HAVE_LIBCAP
 #cmakedefine01 HAVE_SCHED_RESET_ON_FORK
 #cmakedefine01 HAVE_ACCESSIBILITY
+#cmakedefine01 HAVE_LCMS2
 #if HAVE_BREEZE_DECO
 #define BREEZE_KDECORATION_PLUGIN_ID "${BREEZE_KDECORATION_PLUGIN_ID}"
 #endif

plugins/CMakeLists.txt

@@ -12,3 +12,6 @@ endif()
 if (PipeWire_FOUND)
     add_subdirectory(screencast)
 endif()
+if (lcms2_FOUND)
+    add_subdirectory(colord-integration)
+endif()

plugins/colord-integration/CMakeLists.txt

@@ -0,0 +1,37 @@
+set(colordintegration_SOURCES
+    colorddevice.cpp
+    colordintegration.cpp
+    main.cpp
+)
+
+ecm_qt_declare_logging_category(colordintegration_SOURCES
+    HEADER colordlogging.h
+    IDENTIFIER KWIN_COLORD
+    CATEGORY_NAME kwin_colord
+    DEFAULT_SEVERITY Warning
+    DESCRIPTION "KWin colord integration"
+)
+
+set(COLORD_DEVICE_XML org.freedesktop.ColorManager.Device.xml)
+set(COLORD_PROFILE_XML org.freedesktop.ColorManager.Profile.xml)
+set(COLORD_MANAGER_XML org.freedesktop.ColorManager.xml)
+
+set_source_files_properties(${COLORD_MANAGER_XML} PROPERTIES INCLUDE "colordtypes.h")
+set_source_files_properties(${COLORD_MANAGER_XML} PROPERTIES NO_NAMESPACE true)
+set_source_files_properties(${COLORD_MANAGER_XML} PROPERTIES CLASSNAME CdInterface)
+qt5_add_dbus_interface(colordintegration_SOURCES ${COLORD_MANAGER_XML} colordinterface)
+
+set_source_files_properties(${COLORD_DEVICE_XML} PROPERTIES INCLUDE "colordtypes.h")
+set_source_files_properties(${COLORD_DEVICE_XML} PROPERTIES NO_NAMESPACE true)
+set_source_files_properties(${COLORD_DEVICE_XML} PROPERTIES CLASSNAME CdDeviceInterface)
+qt5_add_dbus_interface(colordintegration_SOURCES ${COLORD_DEVICE_XML} colorddeviceinterface)
+
+set_source_files_properties(${COLORD_PROFILE_XML} PROPERTIES INCLUDE "colordtypes.h")
+set_source_files_properties(${COLORD_PROFILE_XML} PROPERTIES NO_NAMESPACE true)
+set_source_files_properties(${COLORD_PROFILE_XML} PROPERTIES CLASSNAME CdProfileInterface)
+qt5_add_dbus_interface(colordintegration_SOURCES ${COLORD_PROFILE_XML} colordprofileinterface)
+
+add_library(colordintegration MODULE ${colordintegration_SOURCES})
+set_target_properties(colordintegration PROPERTIES LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin/kwin/plugins/")
+target_link_libraries(colordintegration kwin lcms2::lcms2)
+install(TARGETS colordintegration DESTINATION ${PLUGIN_INSTALL_DIR}/kwin/plugins/)

plugins/colord-integration/colorddevice.cpp

@@ -0,0 +1,96 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "colorddevice.h"
+#include "abstract_output.h"
+#include "colordlogging.h"
+#include "colordprofileinterface.h"
+
+#include <lcms2.h>
+
+namespace KWin
+{
+
+ColordDevice::ColordDevice(AbstractOutput *output, QObject *parent)
+    : QObject(parent)
+    , m_output(output)
+{
+}
+
+AbstractOutput *ColordDevice::output() const
+{
+    return m_output;
+}
+
+QDBusObjectPath ColordDevice::objectPath() const
+{
+    return m_colordInterface ? QDBusObjectPath(m_colordInterface->path()) : QDBusObjectPath();
+}
+
+void ColordDevice::initialize(const QDBusObjectPath &devicePath)
+{
+    m_colordInterface = new CdDeviceInterface(QStringLiteral("org.freedesktop.ColorManager"),
+                                              devicePath.path(), QDBusConnection::systemBus(), this);
+    connect(m_colordInterface, &CdDeviceInterface::Changed, this, &ColordDevice::updateProfile);
+
+    updateProfile();
+}
+
+void ColordDevice::updateProfile()
+{
+    const QList<QDBusObjectPath> profiles = m_colordInterface->profiles();
+    if (profiles.isEmpty()) {
+        qCDebug(KWIN_COLORD) << m_output->name() << "has no any color profile assigned";
+        return;
+    }
+
+    CdProfileInterface profile(QStringLiteral("org.freedesktop.ColorManager"),
+                               profiles.first().path(), QDBusConnection::systemBus());
+    if (!profile.isValid()) {
+        qCWarning(KWIN_COLORD) << profiles.first() << "is an invalid color profile";
+        return;
+    }
+
+    cmsHPROFILE handle = cmsOpenProfileFromFile(profile.filename().toUtf8(), "r");
+    if (!handle) {
+        qCWarning(KWIN_COLORD) << "Failed to open profile file" << profile.filename();
+        return;
+    }
+
+    GammaRamp ramp(m_output->gammaRampSize());
+    uint16_t *redChannel = ramp.red();
+    uint16_t *greenChannel = ramp.green();
+    uint16_t *blueChannel = ramp.blue();
+
+    cmsToneCurve **vcgt = static_cast<cmsToneCurve **>(cmsReadTag(handle, cmsSigVcgtTag));
+    if (!vcgt || !vcgt[0]) {
+        qCDebug(KWIN_COLORD) << "Profile" << profile.filename() << "has no VCGT tag";
+
+        for (uint32_t i = 0; i < ramp.size(); ++i) {
+            const uint16_t value = (i * 0xffff) / (ramp.size() - 1);
+
+            redChannel[i] = value;
+            greenChannel[i] = value;
+            blueChannel[i] = value;
+        }
+    } else {
+        for (uint32_t i = 0; i < ramp.size(); ++i) {
+            const uint16_t index = (i * 0xffff) / (ramp.size() - 1);
+
+            redChannel[i] = cmsEvalToneCurve16(vcgt[0], index);
+            greenChannel[i] = cmsEvalToneCurve16(vcgt[1], index);
+            blueChannel[i] = cmsEvalToneCurve16(vcgt[2], index);
+        }
+    }
+
+    cmsCloseProfile(handle);
+
+    if (!m_output->setGammaRamp(ramp)) {
+        qCWarning(KWIN_COLORD) << "Failed to apply color profilie on output" << m_output->name();
+    }
+}
+
+} // namespace KWin

plugins/colord-integration/colorddevice.h

@@ -0,0 +1,38 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include "colorddeviceinterface.h"
+
+#include <QDBusObjectPath>
+#include <QObject>
+#include <QPointer>
+
+namespace KWin
+{
+
+class AbstractOutput;
+
+class ColordDevice : public QObject
+{
+public:
+    explicit ColordDevice(AbstractOutput *output, QObject *parent = nullptr);
+
+    void initialize(const QDBusObjectPath &devicePath);
+
+    AbstractOutput *output() const;
+    QDBusObjectPath objectPath() const;
+
+private Q_SLOTS:
+    void updateProfile();
+
+private:
+    CdDeviceInterface *m_colordInterface = nullptr;
+    QPointer<AbstractOutput> m_output;
+};
+
+} // namespace KWin

plugins/colord-integration/colordintegration.cpp

@@ -0,0 +1,82 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "colordintegration.h"
+#include "abstract_output.h"
+#include "colorddevice.h"
+#include "colordlogging.h"
+#include "main.h"
+#include "platform.h"
+
+#include <QDBusPendingCallWatcher>
+
+namespace KWin
+{
+
+ColordIntegration::ColordIntegration(QObject *parent)
+    : Plugin(parent)
+{
+    qDBusRegisterMetaType<CdStringMap>();
+
+    const Platform *platform = kwinApp()->platform();
+
+    m_colordInterface = new CdInterface(QStringLiteral("org.freedesktop.ColorManager"),
+                                        QStringLiteral("/org/freedesktop/ColorManager"),
+                                        QDBusConnection::systemBus(), this);
+
+    const QVector<AbstractOutput *> outputs = platform->outputs();
+    for (AbstractOutput *output : outputs) {
+        handleOutputAdded(output);
+    }
+
+    connect(platform, &Platform::outputAdded, this, &ColordIntegration::handleOutputAdded);
+    connect(platform, &Platform::outputRemoved, this, &ColordIntegration::handleOutputRemoved);
+}
+
+void ColordIntegration::handleOutputAdded(AbstractOutput *output)
+{
+    ColordDevice *device = new ColordDevice(output, this);
+
+    CdStringMap properties;
+    properties.insert(QStringLiteral("Kind"), QStringLiteral("display"));
+    properties.insert(QStringLiteral("Colorspace"), QStringLiteral("RGB"));
+
+    QDBusPendingReply<QDBusObjectPath> reply =
+            m_colordInterface->CreateDevice(output->name(), QStringLiteral("temp"), properties);
+
+    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(reply, this);
+    connect(watcher, &QDBusPendingCallWatcher::finished, this, [this, device, watcher]() {
+        watcher->deleteLater();
+
+        const QDBusPendingReply<QDBusObjectPath> reply = *watcher;
+        if (reply.isError()) {
+            qCDebug(KWIN_COLORD) << "Failed to add a colord device:" << reply.error();
+            delete device;
+            return;
+        }
+
+        const QDBusObjectPath objectPath = reply.value();
+        if (!device->output()) {
+            m_colordInterface->DeleteDevice(objectPath);
+            delete device;
+            return;
+        }
+
+        device->initialize(objectPath);
+        m_outputToDevice.insert(device->output(), device);
+    });
+}
+
+void ColordIntegration::handleOutputRemoved(AbstractOutput *output)
+{
+    ColordDevice *device = m_outputToDevice.take(output);
+    if (device) {
+        m_colordInterface->DeleteDevice(device->objectPath());
+        delete device;
+    }
+}
+
+} // namespace KWin

plugins/colord-integration/colordintegration.h

@@ -0,0 +1,37 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include "colordinterface.h"
+#include "plugin.h"
+
+#include <QHash>
+#include <QObject>
+
+namespace KWin
+{
+
+class AbstractOutput;
+class ColordDevice;
+
+class KWIN_EXPORT ColordIntegration : public Plugin
+{
+    Q_OBJECT
+
+public:
+    explicit ColordIntegration(QObject *parent = nullptr);
+
+private Q_SLOTS:
+    void handleOutputAdded(AbstractOutput *output);
+    void handleOutputRemoved(AbstractOutput *output);
+
+private:
+    QHash<AbstractOutput *, ColordDevice *> m_outputToDevice;
+    CdInterface *m_colordInterface;
+};
+
+} // namespace KWin

plugins/colord-integration/colordtypes.h

@@ -0,0 +1,14 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <QMap>
+#include <QMetaType>
+#include <QString>
+
+typedef QMap<QString, QString> CdStringMap;
+Q_DECLARE_METATYPE(CdStringMap)

plugins/colord-integration/main.cpp

@@ -0,0 +1,46 @@
+/*
+    SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#include "colordintegration.h"
+#include "main.h"
+
+#include <KPluginFactory>
+
+using namespace KWin;
+
+class KWIN_EXPORT ColordIntegrationFactory : public PluginFactory
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID PluginFactory_iid FILE "metadata.json")
+    Q_INTERFACES(KWin::PluginFactory)
+
+public:
+    explicit ColordIntegrationFactory(QObject *parent = nullptr);
+
+    Plugin *create() const override;
+};
+
+ColordIntegrationFactory::ColordIntegrationFactory(QObject *parent)
+    : PluginFactory(parent)
+{
+}
+
+Plugin *ColordIntegrationFactory::create() const
+{
+    switch (kwinApp()->operationMode()) {
+    case Application::OperationModeX11:
+        return nullptr;
+    case Application::OperationModeXwayland:
+    case Application::OperationModeWaylandOnly:
+        return new ColordIntegration();
+    default:
+        return nullptr;
+    }
+}
+
+K_EXPORT_PLUGIN_VERSION(KWIN_PLUGIN_API_VERSION)
+
+#include "main.moc"

plugins/colord-integration/metadata.json

@@ -0,0 +1,6 @@
+{
+    "KPlugin": {
+        "EnabledByDefault": true,
+        "Id": "kwin5_plugin_colord"
+    }
+}

plugins/colord-integration/org.freedesktop.ColorManager.Device.xml

@@ -0,0 +1,40 @@
+<!DOCTYPE node PUBLIC
+"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"https://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/" xmlns:doc="https://www.freedesktop.org/dbus/1.0/doc.dtd">
+  <interface name='org.freedesktop.ColorManager.Device'>
+    <doc:doc>
+      <doc:description>
+        <doc:para>
+          The interface used for querying color parameters for a specific device.
+        </doc:para>
+      </doc:description>
+    </doc:doc>
+
+    <!--***********************************************************-->
+    <property name='Profiles' type='ao' access='read'>
+      <doc:doc>
+        <doc:description>
+          <doc:para>
+            The profile paths associated with this device.
+            Profiles are returned even if the device is disabled or
+            is profiling, and clients should not assume that the first
+            profile in this array should be applied.
+          </doc:para>
+        </doc:description>
+      </doc:doc>
+    </property>
+
+    <!-- ************************************************************ -->
+    <signal name='Changed'>
+      <doc:doc>
+        <doc:description>
+          <doc:para>
+            Some value on the interface has changed.
+          </doc:para>
+        </doc:description>
+      </doc:doc>
+    </signal>
+
+  </interface>
+</node>

plugins/colord-integration/org.freedesktop.ColorManager.Profile.xml

@@ -0,0 +1,26 @@
+<!DOCTYPE node PUBLIC
+"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"https://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/" xmlns:doc="https://www.freedesktop.org/dbus/1.0/doc.dtd">
+  <interface name='org.freedesktop.ColorManager.Profile'>
+    <doc:doc>
+      <doc:description>
+        <doc:para>
+          The interface used for querying color profiles.
+        </doc:para>
+      </doc:description>
+    </doc:doc>
+
+    <!--***********************************************************-->
+    <property name='Filename' type='s' access='read'>
+      <doc:doc>
+        <doc:description>
+          <doc:para>
+            The profile filename, if one exists.
+          </doc:para>
+        </doc:description>
+      </doc:doc>
+    </property>
+
+  </interface>
+</node>

plugins/colord-integration/org.freedesktop.ColorManager.xml

@@ -0,0 +1,125 @@
+<!DOCTYPE node PUBLIC
+"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"https://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/" xmlns:doc="https://www.freedesktop.org/dbus/1.0/doc.dtd">
+  <interface name='org.freedesktop.ColorManager'>
+    <doc:doc>
+      <doc:description>
+        <doc:para>
+          The interface used for querying color parameters for the system.
+        </doc:para>
+      </doc:description>
+    </doc:doc>
+
+    <!--***********************************************************-->
+    <method name='CreateDevice'>
+      <doc:doc>
+        <doc:description>
+          <doc:para>
+            Creates a device.
+          </doc:para>
+          <doc:para>
+            If the device has profiles added to it in the past, and
+            that profiles exists already, then the new device will be
+            automatically have profiles added to the device.
+            To prevent this from happening, remove the assignment by
+            doing <doc:tt>RemoveProfile</doc:tt> on the relevant
+            device object.
+          </doc:para>
+        </doc:description>
+      </doc:doc>
+      <arg type='s' name='device_id' direction='in'>
+        <doc:doc>
+          <doc:summary>
+            <doc:para>
+              A device ID that is used to map to the device path.
+            </doc:para>
+          </doc:summary>
+        </doc:doc>
+      </arg>
+      <arg type='s' name='scope' direction='in'>
+        <doc:doc>
+          <doc:summary>
+            <doc:para>
+              Options for creating the device. This allows the session
+              color management component to have per-session virtual
+              devices cleaned up automatically or devices that are
+              re-created on each boot.
+            </doc:para>
+          </doc:summary>
+          <doc:list>
+            <doc:item>
+              <doc:term>normal</doc:term>
+              <doc:definition>
+                Normal device.
+              </doc:definition>
+            </doc:item>
+            <doc:item>
+              <doc:term>temp</doc:term>
+              <doc:definition>
+                Device that is removed if the user logs out.
+              </doc:definition>
+            </doc:item>
+            <doc:item>
+              <doc:term>disk</doc:term>
+              <doc:definition>
+                Device that is saved to disk, and restored if the
+                computer is restarted.
+              </doc:definition>
+            </doc:item>
+          </doc:list>
+        </doc:doc>
+      </arg>
+      <annotation name="org.qtproject.QtDBus.QtTypeName.In2" value="CdStringMap"/>
+      <arg type='a{ss}' name='properties' direction='in'>
+        <doc:doc>
+          <doc:summary>
+            <doc:para>
+              Properties to be used when constructing the device.
+            </doc:para>
+            <doc:para>
+              This optional value allows the device to be created with
+              the latency of one bus round-trip, rather than doing
+              a few <doc:tt>SetProperty</doc:tt> methods indervidually.
+            </doc:para>
+            <doc:para>
+              Any properties not interstood by colord will be added as
+              dictionary values to the <doc:tt>Metadata</doc:tt>
+              property.
+            </doc:para>
+          </doc:summary>
+        </doc:doc>
+      </arg>
+      <arg type='o' name='object_path' direction='out'>
+        <doc:doc>
+          <doc:summary>
+            <doc:para>
+              A device path.
+            </doc:para>
+          </doc:summary>
+        </doc:doc>
+      </arg>
+    </method>
+
+    <!--***********************************************************-->
+    <method name='DeleteDevice'>
+      <doc:doc>
+        <doc:description>
+          <doc:para>
+            Deletes a device.
+          </doc:para>
+        </doc:description>
+      </doc:doc>
+      <arg type='o' name='object_path' direction='in'>
+        <doc:doc>
+          <doc:summary>
+            <doc:para>
+              A device path.
+            </doc:para>
+          </doc:summary>
+        </doc:doc>
+      </arg>
+    </method>
+
+  </interface>
+</node>