Cannot EGL working on X11 using XCB with getPlatformDisplayEXT

Graphics / Linux Linux
1

As title says using nvidia xorg driver, I have problem to get working EGL using xcb, is there something missing (I read https://registry.khronos.org/EGL/extensions/EXT/EGL_EXT_platform_xcb.txt and there are nothing to indicate additional parameters)?

Although if I create with XLIB it works fine. I’m using 580.159.04 as it is latest drivers with GTX 1080 support.

Here minimal reproducer:

// compile with: gcc -ggdb3 -lepoxy -lEGL -lxcb test.c -o test
#include <stdio.h>
#include <string.h>
#include <dlfcn.h>
#define MESA_EGL_NO_X11_HEADERS
#define EGL_NO_X11

#include <xcb/xcb.h>
#include <xcb/xcb_aux.h>

#include <epoxy/gl.h>
#include <epoxy/egl.h>

#ifndef EGL_PLATFORM_XCB_EXT
#define EGL_PLATFORM_XCB_EXT 0x31DC
#endif


int main(int argc,char *argv[]) {

    PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplayEXT = (void *) eglGetProcAddress("eglGetPlatformDisplayEXT");

    printf("getPlatformDisplayEXT %p\n",getPlatformDisplayEXT);


    if (argc < 2) {
        fprintf(stderr,"usage: %s xcb|x11\n",argv[0]);
        return 1;
    }

    int egl_major, egl_minor;

    EGLint platform;
    void *platform_param;
    char *what = "";

    if (strcmp(argv[1],"xcb") == 0) {
        what = "xcb";
        platform = EGL_PLATFORM_XCB_EXT;
        xcb_connection_t *conn = xcb_connect(NULL, NULL);
        platform_param = conn;

    } else {
        what = "xlib";
        platform = EGL_PLATFORM_X11_EXT;
        void *lib = dlopen("libX11.so", RTLD_LOCAL | RTLD_LAZY);
        void *(*x_open_display)(void *) =
            (void *) dlsym(lib, "XOpenDisplay");

        void *xdpy = x_open_display(NULL);

        platform_param = xdpy;
    }

    printf("Trying %s\n",what);

    EGLDisplay dpy = getPlatformDisplayEXT(platform, platform_param, NULL);
    printf("dpy %p\n",dpy);

    eglInitialize(dpy,&egl_major,&egl_minor);

    printf("EGL vendor: %s\n",eglQueryString(dpy, EGL_VENDOR));

    return 0;

}

When getPlatformDisplayEXT requested with EGL_PLATFORM_XCB_EXT I getting:

$ ./test xcb
getPlatformDisplayEXT 0x7ffff7e5f180
Trying xcb
dpy 0x5555556b0340
libEGL warning: pci id for fd 4: 10de:2702, driver (null)

pci id for fd 5: 10de:2702, driver (null)
pci id for fd 6: 10de:2702, driver (null)
libEGL warning: egl: failed to create dri2 screen
EGL vendor: Mesa Project

The libglvnd fail to load nvidia vendor and fallbacks to mesa software render.

On other hand calling with xlib (x11 parameter) it works:

$ ./test x11
getPlatformDisplayEXT 0x7ffff7e5f180
Trying xlib
dpy 0x555555661d80
EGL vendor: NVIDIA

note: if I using X11 modesetting driver it behaves correctly