kwin/main_wayland.cpp
Martin Gräßlin 74ae2f503e [wayland] Flush QtWaylands wl_display and KWin's wayland server when processing events
QtWayland and mesa might dead lock KWin if we start rendering a QWindow
before Qt/Mesa got the last frame callback. They perform blocking wayland
event reading on the main gui thread which makes it impossible for KWin
to do the compositing and send the callback.

To workaround this problem we fake a frameRendered directly after each
damage event for a Qt internal window. Unfortunately this is not yet
completely sufficient, thus we also need to ensure that the wayland
events are processed before any events are processed which would cause
a repaint and block. Thus we first flush QtWayland's wl_display and then
our Server connection. If there were any damage events we can be sure
that the frameRendered is sent before Qt attempts to render.
2015-05-18 15:31:40 +02:00

549 lines
20 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2014 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "main_wayland.h"
#include "workspace.h"
#include <config-kwin.h>
// kwin
#include "abstract_backend.h"
#include "wayland_server.h"
#include "xcbutils.h"
// KWayland
#include <KWayland/Server/display.h>
#include <KWayland/Server/seat_interface.h>
// KDE
#include <KLocalizedString>
#include <KPluginLoader>
#include <KPluginMetaData>
// Qt
#include <qplatformdefs.h>
#include <QCommandLineParser>
#include <QtConcurrentRun>
#include <QFile>
#include <QFutureWatcher>
#include <qpa/qwindowsysteminterface.h>
#include <QProcess>
#include <QSocketNotifier>
#include <QThread>
#include <QDebug>
#include <QWindow>
// system
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif // HAVE_UNISTD_H
#include <iostream>
namespace KWin
{
static void sighandler(int)
{
QApplication::exit();
}
static int startXServer(int waylandSocket, int wmFd);
static void readDisplay(int pipe);
//************************************
// ApplicationWayland
//************************************
ApplicationWayland::ApplicationWayland(int &argc, char **argv)
: Application(OperationModeWaylandAndX11, argc, argv)
{
}
ApplicationWayland::~ApplicationWayland()
{
destroyWorkspace();
if (x11Connection()) {
Xcb::setInputFocus(XCB_INPUT_FOCUS_POINTER_ROOT);
xcb_disconnect(x11Connection());
}
}
void ApplicationWayland::performStartup()
{
setOperationMode(m_startXWayland ? OperationModeXwayland : OperationModeWaylandAndX11);
// first load options - done internally by a different thread
createOptions();
waylandServer()->createInternalConnection();
// try creating the Wayland Backend
createInput();
createBackend();
}
void ApplicationWayland::createBackend()
{
AbstractBackend *backend = waylandServer()->backend();
connect(backend, &AbstractBackend::screensQueried, this, &ApplicationWayland::continueStartupWithScreens);
connect(backend, &AbstractBackend::initFailed, this,
[] () {
std::cerr << "FATAL ERROR: backend failed to initialize, exiting now" << std::endl;
::exit(1);
}
);
backend->init();
}
void ApplicationWayland::continueStartupWithScreens()
{
disconnect(waylandServer()->backend(), &AbstractBackend::screensQueried, this, &ApplicationWayland::continueStartupWithScreens);
createScreens();
waylandServer()->initOutputs();
if (!m_startXWayland) {
continueStartupWithX();
return;
}
createCompositor();
int sx[2];
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sx) < 0) {
std::cerr << "FATAL ERROR: failed to open socket to open XCB connection" << std::endl;
exit(1);
return;
}
const int fd = waylandServer()->createXWaylandConnection();
if (fd == -1) {
std::cerr << "FATAL ERROR: failed to open socket for Xwayland" << std::endl;
exit(1);
return;
}
m_xcbConnectionFd = sx[0];
const int xDisplayPipe = startXServer(fd, sx[1]);
QFutureWatcher<void> *watcher = new QFutureWatcher<void>(this);
QObject::connect(watcher, &QFutureWatcher<void>::finished, this, &ApplicationWayland::continueStartupWithX, Qt::QueuedConnection);
QObject::connect(watcher, &QFutureWatcher<void>::finished, watcher, &QFutureWatcher<void>::deleteLater, Qt::QueuedConnection);
watcher->setFuture(QtConcurrent::run(readDisplay, xDisplayPipe));
}
void ApplicationWayland::continueStartupWithX()
{
createX11Connection();
xcb_connection_t *c = x11Connection();
if (!c) {
// about to quit
return;
}
QSocketNotifier *notifier = new QSocketNotifier(xcb_get_file_descriptor(c), QSocketNotifier::Read, this);
auto processXcbEvents = [this, c] {
while (auto event = xcb_poll_for_event(c)) {
updateX11Time(event);
long result = 0;
if (QThread::currentThread()->eventDispatcher()->filterNativeEvent(QByteArrayLiteral("xcb_generic_event_t"), event, &result)) {
free(event);
continue;
}
if (Workspace::self()) {
Workspace::self()->workspaceEvent(event);
}
free(event);
}
xcb_flush(c);
};
connect(notifier, &QSocketNotifier::activated, this, processXcbEvents);
connect(QThread::currentThread()->eventDispatcher(), &QAbstractEventDispatcher::aboutToBlock, this, processXcbEvents);
connect(QThread::currentThread()->eventDispatcher(), &QAbstractEventDispatcher::awake, this, processXcbEvents);
// create selection owner for WM_S0 - magic X display number expected by XWayland
KSelectionOwner owner("WM_S0", c, x11RootWindow());
owner.claim(true);
createAtoms();
setupEventFilters();
// Check whether another windowmanager is running
const uint32_t maskValues[] = {XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT};
ScopedCPointer<xcb_generic_error_t> redirectCheck(xcb_request_check(connection(),
xcb_change_window_attributes_checked(connection(),
rootWindow(),
XCB_CW_EVENT_MASK,
maskValues)));
if (!redirectCheck.isNull()) {
fputs(i18n("kwin_wayland: an X11 window manager is running on the X11 Display.\n").toLocal8Bit().constData(), stderr);
::exit(1);
}
// start the applications passed to us as command line arguments
if (!m_applicationsToStart.isEmpty()) {
QProcessEnvironment environment = QProcessEnvironment::systemEnvironment();
environment.remove(QStringLiteral("WAYLAND_SOCKET"));
environment.remove(QStringLiteral("QT_QPA_PLATFORM"));
environment.remove(QStringLiteral("QT_WAYLAND_DISABLE_WINDOWDECORATION"));
environment.insert(QStringLiteral("DISPLAY"), QString::fromUtf8(qgetenv("DISPLAY")));
// TODO: maybe create a socket per process?
environment.insert(QStringLiteral("WAYLAND_DISPLAY"), waylandServer()->display()->socketName());
for (const QString &application: m_applicationsToStart) {
// note: this will kill the started process when we exit
// this is going to happen anyway as we are the wayland and X server the app connects to
QProcess *p = new QProcess(this);
p->setProcessEnvironment(environment);
p->start(application);
}
}
// HACK: create a QWindow in a thread to force QtWayland to create the client buffer integration
// this performs an eglInitialize which would block as it does a roundtrip to the Wayland server
// in the main thread. By moving into a thread we get the initialize without hitting the problem
// This needs to be done before creating the Workspace as from inside Workspace the dangerous code
// gets hit in the main thread
QFutureWatcher<void> *eglInitWatcher = new QFutureWatcher<void>(this);
connect(eglInitWatcher, &QFutureWatcher<void>::finished, this,
[this, eglInitWatcher] {
eglInitWatcher->deleteLater();
createWorkspace();
Xcb::sync(); // Trigger possible errors, there's still a chance to abort
notifyKSplash();
waylandServer()->createDummyQtWindow();
}
);
eglInitWatcher->setFuture(QtConcurrent::run([] {
QWindow w;
w.setSurfaceType(QSurface::RasterGLSurface);
w.create();
}));
}
void ApplicationWayland::createX11Connection()
{
int screenNumber = 0;
xcb_connection_t *c = nullptr;
if (m_xcbConnectionFd == -1) {
c = xcb_connect(nullptr, &screenNumber);
} else {
c = xcb_connect_to_fd(m_xcbConnectionFd, nullptr);
}
if (int error = xcb_connection_has_error(c)) {
std::cerr << "FATAL ERROR: Creating connection to XServer failed: " << error << std::endl;
exit(1);
return;
}
setX11Connection(c);
// we don't support X11 multi-head in Wayland
setX11ScreenNumber(screenNumber);
setX11RootWindow(defaultScreen()->root);
}
/**
* Starts the Xwayland-Server.
* The new process is started by forking into it.
**/
static int startXServer(int waylandSocket, int wmFd)
{
int pipeFds[2];
if (pipe(pipeFds) != 0) {
std::cerr << "FATAL ERROR failed to create pipe to start Xwayland " << std::endl;
exit(1);
}
pid_t pid = fork();
if (pid == 0) {
// child process - should be turned into X-Server
// writes to pipe, closes read side
close(pipeFds[0]);
char fdbuf[16];
sprintf(fdbuf, "%d", pipeFds[1]);
char wmfdbuf[16];
int fd = dup(wmFd);
if (fd < 0) {
std::cerr << "FATAL ERROR: failed to open socket to open XCB connection" << std::endl;
exit(20);
return -1;
}
sprintf(wmfdbuf, "%d", fd);
int wlfd = dup(waylandSocket);
if (wlfd < 0) {
std::cerr << "FATAL ERROR: failed to open socket for Xwayland" << std::endl;
exit(20);
return -1;
}
qputenv("WAYLAND_SOCKET", QByteArray::number(wlfd));
execlp("Xwayland", "Xwayland", "-displayfd", fdbuf, "-rootless", "-wm", wmfdbuf, (char *)0);
close(pipeFds[1]);
exit(20);
}
// parent process - this is KWin
// reads from pipe, closes write side
close(pipeFds[1]);
return pipeFds[0];
}
static void readDisplay(int pipe)
{
QFile readPipe;
if (!readPipe.open(pipe, QIODevice::ReadOnly)) {
std::cerr << "FATAL ERROR failed to open pipe to start X Server" << std::endl;
exit(1);
}
QByteArray displayNumber = readPipe.readLine();
displayNumber.prepend(QByteArray(":"));
displayNumber.remove(displayNumber.size() -1, 1);
std::cout << "X-Server started on display " << displayNumber.constData() << std::endl;
setenv("DISPLAY", displayNumber.constData(), true);
// close our pipe
close(pipe);
}
EventDispatcher::EventDispatcher(QObject *parent)
: QEventDispatcherUNIX(parent)
{
}
EventDispatcher::~EventDispatcher() = default;
bool EventDispatcher::processEvents(QEventLoop::ProcessEventsFlags flags)
{
waylandServer()->dispatch();
const bool didSendEvents = QEventDispatcherUNIX::processEvents(flags);
return QWindowSystemInterface::sendWindowSystemEvents(flags) || didSendEvents;
}
bool EventDispatcher::hasPendingEvents()
{
return QEventDispatcherUNIX::hasPendingEvents() || QWindowSystemInterface::windowSystemEventsQueued();
}
} // namespace
extern "C"
KWIN_EXPORT int kdemain(int argc, char * argv[])
{
// process command line arguments to figure out whether we have to start Xwayland and the Wayland socket
QByteArray waylandSocket;
for (int i = 1; i < argc; ++i) {
QByteArray arg = QByteArray::fromRawData(argv[i], qstrlen(argv[i]));
if (arg == "--socket" || arg == "-s") {
if (++i < argc) {
waylandSocket = QByteArray::fromRawData(argv[i], qstrlen(argv[i]));
}
continue;
}
if (arg.startsWith("--socket=")) {
waylandSocket = arg.mid(9);
}
}
// set our own event dispatcher to be able to dispatch events before the event loop is started
QAbstractEventDispatcher *eventDispatcher = new KWin::EventDispatcher();
QCoreApplication::setEventDispatcher(eventDispatcher);
KWin::WaylandServer *server = KWin::WaylandServer::create(nullptr);
server->init(waylandSocket);
KWin::Application::setupMalloc();
KWin::Application::setupLocalizedString();
KWin::Application::setupLoggingCategoryFilters();
if (signal(SIGTERM, KWin::sighandler) == SIG_IGN)
signal(SIGTERM, SIG_IGN);
if (signal(SIGINT, KWin::sighandler) == SIG_IGN)
signal(SIGINT, SIG_IGN);
if (signal(SIGHUP, KWin::sighandler) == SIG_IGN)
signal(SIGHUP, SIG_IGN);
// ensure that no thread takes SIGUSR
sigset_t userSiganls;
sigemptyset(&userSiganls);
sigaddset(&userSiganls, SIGUSR1);
sigaddset(&userSiganls, SIGUSR2);
pthread_sigmask(SIG_BLOCK, &userSiganls, nullptr);
// enforce wayland plugin, unfortunately command line switch has precedence
setenv("QT_QPA_PLATFORM", "wayland", true);
#if (QT_VERSION < QT_VERSION_CHECK(5, 4, 2))
// TODO: remove warning once we depend on Qt 5.5
qWarning() << "QtWayland 5.4.2 required, application might freeze if not present!";
#endif
qunsetenv("QT_DEVICE_PIXEL_RATIO");
qputenv("WAYLAND_SOCKET", QByteArray::number(server->createQtConnection()));
qputenv("QT_WAYLAND_DISABLE_WINDOWDECORATION", "1");
KWin::ApplicationWayland a(argc, argv);
a.setupTranslator();
server->setParent(&a);
KWin::Application::createAboutData();
QCommandLineOption xwaylandOption(QStringLiteral("xwayland"),
i18n("Start a rootless Xwayland server."));
QCommandLineOption waylandSocketOption(QStringList{QStringLiteral("s"), QStringLiteral("socket")},
i18n("Name of the Wayland socket to listen on. If not set \"wayland-0\" is used."),
QStringLiteral("socket"));
QCommandLineOption windowedOption(QStringLiteral("windowed"),
i18n("Use a nested compositor in windowed mode."));
QCommandLineOption framebufferOption(QStringLiteral("framebuffer"),
i18n("Render to framebuffer."));
QCommandLineOption framebufferDeviceOption(QStringLiteral("fb-device"),
i18n("The framebuffer device to render to."),
QStringLiteral("fbdev"));
framebufferDeviceOption.setDefaultValue(QStringLiteral("/dev/fb0"));
QCommandLineOption x11DisplayOption(QStringLiteral("x11-display"),
i18n("The X11 Display to use in windowed mode on platform X11."),
QStringLiteral("display"));
QCommandLineOption waylandDisplayOption(QStringLiteral("wayland-display"),
i18n("The Wayland Display to use in windowed mode on platform Wayland."),
QStringLiteral("display"));
QCommandLineOption widthOption(QStringLiteral("width"),
i18n("The width for windowed mode. Default width is 1024."),
QStringLiteral("width"));
widthOption.setDefaultValue(QString::number(1024));
QCommandLineOption heightOption(QStringLiteral("height"),
i18n("The height for windowed mode. Default height is 768."),
QStringLiteral("height"));
heightOption.setDefaultValue(QString::number(768));
QCommandLineParser parser;
a.setupCommandLine(&parser);
parser.addOption(xwaylandOption);
parser.addOption(waylandSocketOption);
parser.addOption(windowedOption);
parser.addOption(x11DisplayOption);
parser.addOption(waylandDisplayOption);
parser.addOption(framebufferOption);
parser.addOption(framebufferDeviceOption);
parser.addOption(widthOption);
parser.addOption(heightOption);
#if HAVE_LIBHYBRIS
QCommandLineOption hwcomposerOption(QStringLiteral("hwcomposer"), i18n("Use libhybris hwcomposer"));
parser.addOption(hwcomposerOption);
#endif
#if HAVE_INPUT
QCommandLineOption libinputOption(QStringLiteral("libinput"),
i18n("Enable libinput support for input events processing. Note: never use in a nested session."));
parser.addOption(libinputOption);
#endif
#if HAVE_DRM
QCommandLineOption drmOption(QStringLiteral("drm"), i18n("Render through drm node."));
parser.addOption(drmOption);
#endif
parser.addPositionalArgument(QStringLiteral("applications"),
i18n("Applications to start once Wayland and Xwayland server are started"),
QStringLiteral("[/path/to/application...]"));
parser.process(a);
a.processCommandLine(&parser);
#if HAVE_INPUT
KWin::Application::setUseLibinput(parser.isSet(libinputOption));
#endif
QString pluginName;
QSize initialWindowSize;
QByteArray deviceIdentifier;
if (parser.isSet(windowedOption) && parser.isSet(framebufferOption)) {
std::cerr << "FATAL ERROR Cannot have both --windowed and --framebuffer" << std::endl;
return 1;
}
#if HAVE_DRM
if (parser.isSet(drmOption) && (parser.isSet(windowedOption) || parser.isSet(framebufferOption))) {
std::cerr << "FATAL ERROR Cannot have both --windowed/--framebuffer and --drm" << std::endl;
return 1;
}
if (parser.isSet(drmOption)) {
pluginName = QStringLiteral("KWinWaylandDrmBackend");
}
#endif
if (parser.isSet(windowedOption)) {
bool ok = false;
const int width = parser.value(widthOption).toInt(&ok);
if (!ok) {
std::cerr << "FATAL ERROR incorrect value for width" << std::endl;
return 1;
}
const int height = parser.value(heightOption).toInt(&ok);
if (!ok) {
std::cerr << "FATAL ERROR incorrect value for height" << std::endl;
return 1;
}
initialWindowSize = QSize(width, height);
if (parser.isSet(x11DisplayOption)) {
deviceIdentifier = parser.value(x11DisplayOption).toUtf8();
} else if (!parser.isSet(waylandDisplayOption)) {
deviceIdentifier = qgetenv("DISPLAY");
}
if (!deviceIdentifier.isEmpty()) {
pluginName = QStringLiteral("KWinWaylandX11Backend");
} else {
if (parser.isSet(waylandDisplayOption)) {
deviceIdentifier = parser.value(waylandDisplayOption).toUtf8();
} else if (!parser.isSet(x11DisplayOption)) {
deviceIdentifier = qgetenv("WAYLAND_DISPLAY");
}
if (!deviceIdentifier.isEmpty()) {
pluginName = QStringLiteral("KWinWaylandWaylandBackend");
}
}
}
if (parser.isSet(framebufferOption)) {
pluginName = QStringLiteral("KWinWaylandFbdevBackend");
deviceIdentifier = parser.value(framebufferDeviceOption).toUtf8();
}
#if HAVE_LIBHYBRIS
if (parser.isSet(hwcomposerOption)) {
pluginName = QStringLiteral("KWinWaylandHwcomposerBackend");
}
#endif
const auto pluginCandidates = KPluginLoader::findPlugins(QStringLiteral("org.kde.kwin.waylandbackends"),
[&pluginName] (const KPluginMetaData &plugin) {
return plugin.pluginId() == pluginName;
}
);
if (pluginCandidates.isEmpty()) {
std::cerr << "FATAL ERROR: could not find a backend" << std::endl;
return 1;
}
for (const auto &candidate: pluginCandidates) {
if (qobject_cast<KWin::AbstractBackend*>(candidate.instantiate())) {
break;
}
}
if (!server->backend()) {
std::cerr << "FATAL ERROR: could not instantiate a backend" << std::endl;
return 1;
}
server->backend()->setParent(server);
if (!deviceIdentifier.isEmpty()) {
server->backend()->setDeviceIdentifier(deviceIdentifier);
}
if (initialWindowSize.isValid()) {
server->backend()->setInitialWindowSize(initialWindowSize);
}
a.setStartXwayland(parser.isSet(xwaylandOption));
a.setApplicationsToStart(parser.positionalArguments());
a.start();
return a.exec();
}