[desktop] Prefer X11, but allow Wayland (with a warning) (#4579)

Use `xcb;wayland` as the default value for `QT_QPA_PLATFORM` which will
always try X11 first, then only fallback to Wayland if, for some reason,
X11 is unavailable or unable to initialize.

This also prints a warning to the log if the backend is wayland. Might
be promoted to a warning dialog if this becomes a consistent-enough
issue to warrant a more obvious warning.

Requires removing the wayland hook from the AppImage

Signed-off-by: crueter <crueter@eden-emu.dev>

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md).
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4579
Reviewed-by: lizzie <lizzie@eden-emu.dev>

src/qt_common/CMakeLists.txt

@@ -42,10 +42,6 @@ add_library(qt_common STATIC
     render/context.h
     render/emu_thread.h render/emu_thread.cpp)
 
-if (UNIX)
-    target_sources(qt_common PRIVATE gui_settings.cpp gui_settings.h)
-endif()
-
 create_target_directory_groups(qt_common)
 
 if (USE_DISCORD_PRESENCE)

src/qt_common/config/shared_translation.cpp

@@ -345,10 +345,6 @@ std::unique_ptr<TranslationMap> InitializeTranslations(QObject* parent) {
 
     // Linux
     INSERT(UISettings, enable_gamemode, tr("Enable Gamemode"), QString());
-#ifdef __unix__
-    INSERT(UISettings, gui_force_x11, tr("Force X11 as Graphics Backend"), QString());
-    INSERT(UISettings, gui_hide_backend_warning, QString(), QString());
-#endif
 
     // Ui Debugging
 

src/qt_common/config/uisettings.h

@@ -148,11 +148,6 @@ struct Values {
                                             false,
 #endif
                                             "enable_gamemode", Category::UiGeneral};
-#ifdef __unix__
-    SwitchableSetting<bool> gui_force_x11{linkage, false, "gui_force_x11", Category::UiGeneral};
-    Setting<bool> gui_hide_backend_warning{linkage, false, "gui_hide_backend_warning",
-                                           Category::UiGeneral};
-#endif
 
     // Discord RPC
     Setting<bool> enable_discord_presence{linkage, false, "enable_discord_presence", Category::Ui};

src/qt_common/gui_settings.cpp

@@ -1,26 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#include "common/fs/fs.h"
-#include "common/fs/path_util.h"
-#include "gui_settings.h"
-
-namespace FS = Common::FS;
-
-namespace GraphicsBackend {
-
-QString GuiConfigPath() {
-    return QString::fromStdString(
-        FS::PathToUTF8String(FS::GetEdenPath(FS::EdenPath::ConfigDir) / "gui_config.ini"));
-}
-
-void SetForceX11(bool state) {
-    (void)FS::CreateParentDir(GuiConfigPath().toStdString());
-    QSettings(GuiConfigPath(), QSettings::IniFormat).setValue("gui_force_x11", state);
-}
-
-bool GetForceX11() {
-    return QSettings(GuiConfigPath(), QSettings::IniFormat).value("gui_force_x11", false).toBool();
-}
-
-} // namespace GraphicsBackend

src/qt_common/gui_settings.h

@@ -1,15 +0,0 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#pragma once
-
-#include <QSettings>
-#include <QString>
-
-namespace GraphicsBackend {
-
-QString GuiConfigPath();
-void SetForceX11(bool state);
-bool GetForceX11();
-
-} // namespace GraphicsBackend

src/qt_common/qt_common.cpp

@@ -27,7 +27,6 @@
 #include <QMessageBox>
 
 #include <thread>
-#include <JlCompress.h>
 #include <QPainter>
 
 #if !defined(WIN32) && !defined(__APPLE__)
@@ -37,7 +36,6 @@
 #endif
 
 #ifdef _WIN32
-#include <QApplication>
 #include <QSettings>
 #include <windows.h>
 #include "common/windows/timer_resolution.h"
@@ -277,6 +275,14 @@ void Init(QWidget* root) {
 
     // Remove cached contents generated during the previous session
     RemoveCachedContents();
+
+    // Platform checks
+    const auto qpa = QGuiApplication::platformName();
+    LOG_INFO(Frontend, "Qt Platform Backend: {}", qpa.toStdString());
+    if (qpa == QStringLiteral("wayland"))
+        LOG_WARNING(
+            Frontend,
+            "Platform backend is set to Wayland, which may cause performance/stability issues");
 }
 
 std::filesystem::path GetEdenCommand() {
@@ -325,4 +331,47 @@ QPixmap CreateCirclePixmapFromColor(const QColor& color) {
     return circle_pixmap;
 }
 
+#ifdef _WIN32
+// TODO(crueter): Does this affect Qt 6 at all?
+static void OverrideWindowsFont() {
+    // Qt5 chooses these fonts on Windows and they have fairly ugly alphanumeric/cyrillic characters
+    // Asking to use "MS Shell Dlg 2" gives better other chars while leaving the Chinese Characters.
+    const QString startup_font = QGuiApplication::font().family();
+    const QStringList ugly_fonts = {QStringLiteral("SimSun"), QStringLiteral("PMingLiU")};
+    if (ugly_fonts.contains(startup_font)) {
+        QGuiApplication::setFont(QFont(QStringLiteral("MS Shell Dlg 2"), 9, QFont::Normal));
+    }
+}
+#endif
+
+void SetupApplication() {
+    // Init settings params
+    QCoreApplication::setOrganizationName(QStringLiteral("eden"));
+    QCoreApplication::setApplicationName(QStringLiteral("eden"));
+
+#ifdef __unix__
+    // Set the DISPLAY variable in order to open web browsers
+    // TODO (lat9nq): Find a better solution for AppImages to start external applications
+    if (QString::fromLocal8Bit(qgetenv("DISPLAY")).isEmpty()) {
+        qputenv("DISPLAY", ":0");
+    }
+
+    // Always prefer X11 but allow Wayland if the user is missing X11 for some reason.
+    if (qEnvironmentVariableIsEmpty("QT_QPA_PLATFORM"))
+        qputenv("QT_QPA_PLATFORM", "xcb;wayland");
+
+    // Fix the Wayland appId. This needs to match the name of the .desktop file without the .desktop
+    // suffix.
+    QGuiApplication::setDesktopFileName(QStringLiteral("dev.eden_emu.eden"));
+#endif
+
+    // Enables the core to make the qt created contexts current on std::threads
+    QCoreApplication::setAttribute(Qt::AA_DontCheckOpenGLContextThreadAffinity);
+
+    // Make the app look a little better.
+#ifdef _WIN32
+    OverrideWindowsFont();
+#endif
+}
+
 } // namespace QtCommon

src/qt_common/qt_common.h

@@ -42,6 +42,9 @@ void Init(QWidget* root);
 void SetupContentProviders();
 void SetupHID();
 
+// setup env vars, scaling, and app attributes
+void SetupApplication();
+
 const QString tr(const char* str);
 const QString tr(const std::string& str);
 

src/yuzu/main.cpp

@@ -8,12 +8,11 @@
 #include <cstring>
 #include "dedicated_room/yuzu_room.h"
 #endif
-#ifdef __unix__
-#include "qt_common/gui_settings.h"
-#endif
 
 #ifndef _WIN32
 #include <sys/resource.h>
+#else
+#include <QScreen>
 #endif
 
 #if defined(__APPLE__)
@@ -24,20 +23,7 @@
 
 #include "main_window.h"
 
-#ifdef _WIN32
-#include <QScreen>
-
-static void OverrideWindowsFont() {
-    // Qt5 chooses these fonts on Windows and they have fairly ugly alphanumeric/cyrillic characters
-    // Asking to use "MS Shell Dlg 2" gives better other chars while leaving the Chinese Characters.
-    const QString startup_font = QApplication::font().family();
-    const QStringList ugly_fonts = {QStringLiteral("SimSun"), QStringLiteral("PMingLiU")};
-    if (ugly_fonts.contains(startup_font)) {
-        QApplication::setFont(QFont(QStringLiteral("MS Shell Dlg 2"), 9, QFont::Normal));
-    }
-}
-#endif
-
+// TODO(crueter): This is very annoying, see if there are any other solutions.
 static Qt::HighDpiScaleFactorRoundingPolicy GetHighDpiRoundingPolicy() {
 #ifdef _WIN32
     // For Windows, we want to avoid scaling artifacts on fractional scaling ratios.
@@ -107,10 +93,6 @@ int main(int argc, char* argv[]) {
     Breakpad::InstallCrashHandler();
 #endif
 
-    // Init settings params
-    QCoreApplication::setOrganizationName(QStringLiteral("eden"));
-    QCoreApplication::setApplicationName(QStringLiteral("eden"));
-
     // Increases the maximum open file limit.
     // TODO: This should be common to all frontends.
 #ifdef _WIN32
@@ -149,31 +131,10 @@ int main(int argc, char* argv[]) {
     chdir(Common::FS::PathToUTF8String(bin_path).c_str());
 #endif
 
-#ifdef __unix__
-    // Set the DISPLAY variable in order to open web browsers
-    // TODO (lat9nq): Find a better solution for AppImages to start external applications
-    if (QString::fromLocal8Bit(qgetenv("DISPLAY")).isEmpty()) {
-        qputenv("DISPLAY", ":0");
-    }
-
-    if (GraphicsBackend::GetForceX11() && qEnvironmentVariableIsEmpty("QT_QPA_PLATFORM"))
-        qputenv("QT_QPA_PLATFORM", "xcb");
-
-    // Fix the Wayland appId. This needs to match the name of the .desktop file without the .desktop
-    // suffix.
-    QGuiApplication::setDesktopFileName(QStringLiteral("dev.eden_emu.eden"));
-#endif
+    QtCommon::SetupApplication();
 
     auto rounding_policy = GetHighDpiRoundingPolicy();
-    QApplication::setHighDpiScaleFactorRoundingPolicy(rounding_policy);
-
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-    // Disables the "?" button on all dialogs. Disabled by default on Qt6.
-    QCoreApplication::setAttribute(Qt::AA_DisableWindowContextHelpButton);
-#endif
-
-    // Enables the core to make the qt created contexts current on std::threads
-    QCoreApplication::setAttribute(Qt::AA_DontCheckOpenGLContextThreadAffinity);
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(rounding_policy);
 
 #ifdef _WIN32
     QApplication::setStyle(QStringLiteral("windowsvista"));
@@ -181,21 +142,6 @@ int main(int argc, char* argv[]) {
 
     QApplication app(argc, argv);
 
-#ifdef _WIN32
-    OverrideWindowsFont();
-#endif
-
-    // Workaround for QTBUG-85409, for Suzhou numerals the number 1 is actually \u3021
-    // so we can see if we get \u3008 instead
-    // TL;DR all other number formats are consecutive in unicode code points
-    // This bug is fixed in Qt6, specifically 6.0.0-alpha1
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-    const QLocale locale = QLocale::system();
-    if (QStringLiteral("\u3008") == locale.toString(1)) {
-        QLocale::setDefault(QLocale::system().name());
-    }
-#endif
-
     // Qt changes the locale and causes issues in float conversion using std::to_string() when
     // generating shaders
     setlocale(LC_ALL, "C");

src/yuzu/main_window.cpp

@@ -184,7 +184,6 @@ static FileSys::VirtualFile VfsDirectoryCreateFileWrapper(const FileSys::Virtual
 #include <csignal>
 #include <QSocketNotifier>
 #include <sys/socket.h>
-#include "qt_common/gui_settings.h"
 
 #endif
 
@@ -452,10 +451,6 @@ MainWindow::MainWindow(bool has_broken_vulkan)
     // Gen keys if necessary
     OnCheckFirmwareDecryption();
 
-#ifdef __unix__
-    OnCheckGraphicsBackend();
-#endif
-
     // Check for orphaned profiles and reset profile data if necessary
     QtCommon::Content::FixProfiles();
 
@@ -3475,9 +3470,6 @@ void MainWindow::OnConfigure() {
     const bool old_discord_presence = UISettings::values.enable_discord_presence.GetValue();
     const auto old_language_index = Settings::values.language_index.GetValue();
     const bool old_gamemode = UISettings::values.enable_gamemode.GetValue();
-#ifdef __unix__
-    const bool old_force_x11 = UISettings::values.gui_force_x11.GetValue();
-#endif
 
     Settings::SetConfiguringGlobal(true);
     ConfigureDialog configure_dialog(this, hotkey_registry, input_subsystem.get(),
@@ -3542,11 +3534,6 @@ void MainWindow::OnConfigure() {
     if (UISettings::values.enable_gamemode.GetValue() != old_gamemode) {
         SetGamemodeEnabled(UISettings::values.enable_gamemode.GetValue());
     }
-#ifdef __unix__
-    if (UISettings::values.gui_force_x11.GetValue() != old_force_x11) {
-        GraphicsBackend::SetForceX11(UISettings::values.gui_force_x11.GetValue());
-    }
-#endif
 
     if (!multiplayer_state->IsHostingPublicRoom()) {
         multiplayer_state->UpdateCredentials();
@@ -4430,56 +4417,6 @@ void MainWindow::OnCheckFirmwareDecryption() {
     UpdateMenuState();
 }
 
-#ifdef __unix__
-void MainWindow::OnCheckGraphicsBackend() {
-    const QString platformName = QGuiApplication::platformName();
-    const QByteArray qtPlatform = qgetenv("QT_QPA_PLATFORM");
-
-    if (platformName == QStringLiteral("xcb") || qtPlatform == "xcb")
-        return;
-
-    const bool isWayland =
-        platformName.startsWith(QStringLiteral("wayland"), Qt::CaseInsensitive) ||
-        qtPlatform.startsWith("wayland");
-    if (!isWayland)
-        return;
-
-    const bool currently_hidden = UISettings::values.gui_hide_backend_warning.GetValue();
-    if (currently_hidden)
-        return;
-
-    QMessageBox msgbox(this);
-    msgbox.setWindowTitle(tr("Wayland Detected!"));
-    msgbox.setText(
-        tr("Wayland is known to have significant performance issues and mysterious bugs.\n"
-           "It's recommended to use X11 instead.\n\n"
-           "Would you like to force it for future launches?"));
-    msgbox.setIcon(QMessageBox::Warning);
-
-    QPushButton* okButton = msgbox.addButton(tr("Use X11"), QMessageBox::AcceptRole);
-    msgbox.addButton(tr("Continue with Wayland"), QMessageBox::RejectRole);
-    msgbox.setDefaultButton(okButton);
-
-    QCheckBox* cb = new QCheckBox(tr("Don't show again"), &msgbox);
-    cb->setChecked(currently_hidden);
-    msgbox.setCheckBox(cb);
-
-    msgbox.exec();
-
-    const bool hide = cb->isChecked();
-    if (hide != currently_hidden) {
-        UISettings::values.gui_hide_backend_warning.SetValue(hide);
-    }
-
-    if (msgbox.clickedButton() == okButton) {
-        UISettings::values.gui_force_x11.SetValue(true);
-        GraphicsBackend::SetForceX11(true);
-        QMessageBox::information(this, tr("Restart Required"),
-                                 tr("Restart Eden to apply the X11 backend."));
-    }
-}
-#endif
-
 bool MainWindow::CheckFirmwarePresence() {
     return FirmwareManager::CheckFirmwarePresence(*QtCommon::system.get());
 }

src/yuzu/main_window.h

@@ -427,9 +427,6 @@ private slots:
     void OnCreateHomeMenuApplicationMenuShortcut();
     void OnCaptureScreenshot();
     void OnCheckFirmwareDecryption();
-#ifdef __unix__
-    void OnCheckGraphicsBackend();
-#endif
     void OnLanguageChanged(const QString& locale);
     void OnMouseActivity();
     bool OnShutdownBegin();