WSL2中PyQtWebEngine及GLX创建GL上下文失败求助

问题描述 #

在Windows 11的WSL2（Ubuntu 22.04）实例中运行基于PyQt6 PyQtWebEngine的浏览器程序时出现崩溃，错误提示GL上下文创建失败。后续用C++代码复现了相同的GL上下文创建问题。

Python复现代码 #

import sys
from PyQt6.QtCore import *
from PyQt6.QtWidgets import *
from PyQt6.QtGui import QAction
from PyQt6.QtWebEngineWidgets import QWebEngineView

class BrowserApp(QMainWindow):

    def __init__(self):
        super().__init__()

        # Set up the browser
        self.browser = QWebEngineView()
        self.browser.setUrl(QUrl("https://www.google.com"))

        self.setCentralWidget(self.browser)
        self.showMaximized()

        # navigation bar
        navbar = QToolBar()
        self.addToolBar(navbar)

        back_btn = QAction("Back", self)
        back_btn.triggered.connect(self.browser.back)
        navbar.addAction(back_btn)

        forward_btn = QAction("Forward", self)
        forward_btn.triggered.connect(self.browser.forward)
        navbar.addAction(forward_btn)

        reload_btn = QAction("Reload", self)
        reload_btn.triggered.connect(self.browser.reload)
        navbar.addAction(reload_btn)

        home_btn = QAction("Home", self)
        home_btn.triggered.connect(self.navigate_home)
        navbar.addAction(home_btn)

        self.url_bar = QLineEdit()
        self.url_bar.returnPressed.connect(self.navigate_to_url)
        navbar.addWidget(self.url_bar)

        self.browser.urlChanged.connect(self.update_url)

    def navigate_home(self):
        self.browser.setUrl(QUrl("https://www.google.com"))

    def navigate_to_url(self):
        url = self.url_bar.text()
        self.browser.setUrl(QUrl(url))

    def update_url(self, q: QUrl):
        self.url_bar.setText(q.toString())

app = QApplication(sys.argv)
window = BrowserApp()
sys.exit(app.exec())

Python程序运行错误信息 #

D3D12: Removing Device.
[68941:68967:0907/170452.006866:ERROR:gl_context_egl.cc(370)] eglCreateContext failed with error EGL_BAD_ALLOC
[68941:68967:0907/170452.006913:ERROR:gpu_channel_manager.cc(888)] Failed to create GLES3 context, fallback to GLES2.
Segmentation fault

系统配置 #

• 操作系统：Microsoft Windows 11
• CPU：13th Gen Intel(R) Core(TM) i7-13700 @ 2100 MHz
• GPU：Intel(R) UHD Graphics 770

C++复现代码 #

#include <iostream>
#include <GL/glx.h>
#include <X11/Xlib.h>

int IgnoreX11Errors(Display *display, XErrorEvent *error) {
    return 0;  // Ignore errors
}

int main() {
    Display* display = XOpenDisplay(nullptr);
    if (!display) {
        std::cerr << "Unable to open X display." << std::endl;
        return -1;
    }

    static int visualAttribs[] = {
        GLX_X_RENDERABLE, True,
        GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
        GLX_RENDER_TYPE, GLX_RGBA_BIT,
        GLX_X_VISUAL_TYPE, GLX_TRUE_COLOR,
        GLX_RED_SIZE, 8,
        GLX_GREEN_SIZE, 8,
        GLX_BLUE_SIZE, 8,
        GLX_ALPHA_SIZE, 8,
        GLX_DEPTH_SIZE, 24,
        GLX_STENCIL_SIZE, 8,
        GLX_DOUBLEBUFFER, True,
        None
    };

    int numConfigs;
    GLXFBConfig* fbConfigs = glXChooseFBConfig(display, DefaultScreen(display), visualAttribs, &numConfigs);
    if (!fbConfigs) {
        std::cerr << "Failed to retrieve framebuffer configs." << std::endl;
        XCloseDisplay(display);
        return -1;
    }

    GLXFBConfig config = fbConfigs[0];
    XFree(fbConfigs);

    PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB = 
        (PFNGLXCREATECONTEXTATTRIBSARBPROC) glXGetProcAddressARB((const GLubyte*) "glXCreateContextAttribsARB");

    if (!glXCreateContextAttribsARB) {
        std::cerr << "glXCreateContextAttribsARB is not available." << std::endl;
        XCloseDisplay(display);
        return -1;
    }

    int contextAttribs[] = {
        GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
        GLX_CONTEXT_MINOR_VERSION_ARB, 5,
        None
    };

    auto old_error_handler = XSetErrorHandler(IgnoreX11Errors);
    GLXContext context = glXCreateContextAttribsARB(display, config, 0, True, contextAttribs);
    XSetErrorHandler(old_error_handler);

    if (!context) {
        std::cerr << "Failed to create GL context with glXCreateContextAttribsARB." << std::endl;
        XCloseDisplay(display);
        return -1;
    }

    std::cout << "GL context created successfully." << std::endl;

    glXDestroyContext(display, context);
    XCloseDisplay(display);
    return 0;
}

C++代码编译命令 #

g++ tmp.cpp -o tmp -lGL -lX11

C++程序运行错误信息 #

Failed to create GL context with glXCreateContextAttribsARB.

排查思路与解决建议 #

1. 降低GL上下文版本要求 #

程序尝试创建GL 4.5上下文失败，WSLg对高版本GL的支持可能有限。

• 修改C++代码中的上下文版本为3.2或更低，测试能否创建成功：

  int contextAttribs[] = {
      GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
      GLX_CONTEXT_MINOR_VERSION_ARB, 2,
      None
  };
  

• 对PyQtWebEngine，可通过环境变量强制使用低版本GL或禁用GPU加速：

  # 强制使用桌面GL并忽略GPU黑名单
  export QTWEBENGINE_CHROMIUM_FLAGS="--use-gl=desktop --ignore-gpu-blacklist --disable-gpu-driver-bug-workarounds"
  # 直接禁用GPU加速
  export QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"
  

  运行Python程序时带上该环境变量即可。

2. 更新WSL2与GPU驱动 #

• 执行wsl --update更新WSL2内核及组件，确保WSLg功能处于最新状态
• 前往Intel官网下载并安装最新版UHD Graphics 770驱动，Windows侧的GPU驱动版本直接影响WSLg的GL支持

3. 检查WSLg配置 #

确保WSLg的GPU加速功能正常启用：

• 查看或创建~/.wslconfig文件，添加以下配置：

  [wsl2]
  guiApplications=true
  drmRenderDevice=/dev/dri/renderD128
  

• 执行wsl --shutdown关闭WSL实例，重新启动后生效

4. 验证基础GL支持 #

安装mesa-utils工具查看WSL中支持的GL版本：

sudo apt install mesa-utils
glxinfo | grep "OpenGL version"

如果输出的版本低于4.5，说明当前WSLg不支持高版本GL，只能降级程序的GL要求。

5. 测试无GPU加速模式 #

直接禁用PyQtWebEngine的GPU加速运行程序：

QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu" python your_script.py

若程序能正常运行，说明问题根源在GPU加速的GL上下文创建环节。

内容的提问来源于stack exchange，提问作者Tokubara