I want to share one context between PbufferSurface(thread #1) and WindowSurface(thread #2).

PbufferSurface is for virtual area to draw image before wayland display attached.

When VALID DISPLAY device attached, I want to draw image to Window Surface.

On thread #1, I created the context for pbuffer, and then on thread #2, I failed to create context with sharing context from context. (error is 0x3006, EGL_BAD_CONTEXT)

Kernel Version: 5.10 (I checked same source code in kernel 4.10 works.)

I have several questions.

1. Should I share Config as well? I searched, and one answer say that config must be same data.

2. If I should share config also, how it works?
   Because my configs for pbuffer has “EGL_SURFACE_TYPE, EGL_PBUFFER_BIT”, but other config for window surface has “EGL_SURFACE_TYPE, EGL_WINDOW_BIT”.
   So, I couldn’t share the config, when I create window surface, error generated.

3. Can I get any example code or sequence about that? Any platform or languages,,,,
   Just sharing Context between PBuffer Surface <-> Window Surface.

This is sequence what I did,

Main thread

1. eglInitialize()

2. eglChooseConfig()

3. eglCreatePbufferSurface()

4. eglCreateContext()

thread #1

5. eglMakeCurrent()

thread #2

6. eglInitialize()

7. eglChooseConfig()

8. eglCreateWindowSurface()

9. eglCreateContext( get context from (4) ) -> error