xwayland/eglstream: Add more error checking

eglCreateStreamKHR() can fail and return EGL_NO_STREAM_KHR, in which
case there is no point in trying to create a buffer from it.

Similarly, eglCreateStreamProducerSurfaceKHR() also fail and return
EGL_NO_SURFACE, which in turn will be used in eglMakeCurrent() as
draw/read surface, and therefore would mean no draw/read buffer.

In those cases, log the error, and bail out early. That won't solve the
issue but will help with investigating the root cause of issues with
EGLStream backend.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
https://gitlab.freedesktop.org/xorg/xserver/-/issues/1156

hw/xwayland/xwayland-glamor-eglstream.c

@@ -387,6 +387,84 @@ xwl_eglstream_set_window_pixmap(WindowPtr window, PixmapPtr pixmap)
     xwl_screen->screen->SetWindowPixmap = xwl_eglstream_set_window_pixmap;
 }
 
+static const char *
+xwl_eglstream_get_error_str(EGLint error)
+{
+    switch (error) {
+    case EGL_BAD_PARAMETER:
+        return "EGL_BAD_PARAMETER";
+    case EGL_BAD_ATTRIBUTE:
+        return "EGL_BAD_ATTRIBUTE";
+    case EGL_BAD_MATCH:
+        return "EGL_BAD_MATCH";
+    case EGL_BAD_ACCESS:
+        return "EGL_BAD_ACCESS";
+    case EGL_BAD_STATE_KHR:
+        return "EGL_BAD_STATE_KHR";
+    case EGL_BAD_STREAM_KHR:
+        return "EGL_BAD_STREAM_KHR";
+    case EGL_BAD_DISPLAY:
+        return "EGL_BAD_DISPLAY";
+    case EGL_NOT_INITIALIZED:
+        return "EGL_NOT_INITIALIZED";
+    default:
+        return "Unknown error";
+    }
+}
+
+static const char *
+xwl_eglstream_get_stream_state_str(EGLint state)
+{
+    switch (state) {
+    case EGL_STREAM_STATE_CREATED_KHR:
+        return "EGL_STREAM_STATE_CREATED_KHR";
+    case EGL_STREAM_STATE_CONNECTING_KHR:
+        return "EGL_STREAM_STATE_CONNECTING_KHR";
+    case EGL_STREAM_STATE_EMPTY_KHR:
+        return "EGL_STREAM_STATE_EMPTY_KHR";
+    case EGL_STREAM_STATE_NEW_FRAME_AVAILABLE_KHR:
+        return "EGL_STREAM_STATE_NEW_FRAME_AVAILABLE_KHR";
+    case EGL_STREAM_STATE_OLD_FRAME_AVAILABLE_KHR:
+        return "EGL_STREAM_STATE_OLD_FRAME_AVAILABLE_KHR";
+    case EGL_STREAM_STATE_DISCONNECTED_KHR:
+        return "EGL_STREAM_STATE_DISCONNECTED_KHR";
+    default:
+        return "Unknown state";
+    }
+}
+
+static EGLint
+xwl_eglstream_get_state(EGLDisplay egl_display, EGLStreamKHR egl_stream)
+{
+    EGLint state;
+
+    eglQueryStreamKHR(egl_display, egl_stream, EGL_STREAM_STATE_KHR, &state);
+    if (!eglQueryStreamKHR(egl_display, egl_stream,
+                           EGL_STREAM_STATE_KHR, &state)) {
+        EGLint state_error = eglGetError();
+        ErrorF("eglstream: Failed to query state - error 0x%X: %s\n",
+               state_error, xwl_eglstream_get_error_str(state_error));
+        return EGL_FALSE;
+    }
+
+    return state;
+}
+
+
+static void
+xwl_eglstream_print_error(EGLDisplay egl_display,
+                          EGLStreamKHR egl_stream, EGLint error)
+{
+    ErrorF("eglstream: error 0x%X: %s\n", error,
+           xwl_eglstream_get_error_str(error));
+
+    if (error == EGL_BAD_STATE_KHR) {
+        EGLint state = xwl_eglstream_get_state(egl_display, egl_stream);
+        ErrorF("eglstream: stream state 0x%X: %s\n", state,
+               xwl_eglstream_get_stream_state_str(state));
+    }
+}
+
 /* Because we run asynchronously with our wayland compositor, it's possible
  * that an X client event could cause us to begin creating a stream for a
  * pixmap/window combo before the stream for the pixmap this window
@@ -466,6 +544,13 @@ xwl_eglstream_consumer_ready_callback(void *data,
             EGL_NONE
         });
 
+    if (xwl_pixmap->surface == EGL_NO_SURFACE) {
+        ErrorF("eglstream: Failed to create EGLSurface for pixmap\n");
+        xwl_eglstream_print_error(xwl_screen->egl_display,
+                                  xwl_pixmap->stream, eglGetError());
+        goto out;
+    }
+
     DebugF("eglstream: win %d completes eglstream for pixmap %p, congrats!\n",
            pending->window->drawable.id, pending->pixmap);
 
@@ -543,8 +628,16 @@ xwl_eglstream_create_pixmap_and_stream(struct xwl_screen *xwl_screen,
     xwl_pixmap->xwl_screen = xwl_screen;
     xwl_pixmap->surface = EGL_NO_SURFACE;
     xwl_pixmap->stream = eglCreateStreamKHR(xwl_screen->egl_display, NULL);
+    if (xwl_pixmap->stream == EGL_NO_STREAM_KHR) {
+        ErrorF("eglstream: Couldn't create EGL stream.\n");
+        goto fail;
+    }
     stream_fd = eglGetStreamFileDescriptorKHR(xwl_screen->egl_display,
                                               xwl_pixmap->stream);
+    if (stream_fd == EGL_NO_FILE_DESCRIPTOR_KHR) {
+        ErrorF("eglstream: Couldn't get EGL stream file descriptor.\n");
+        goto fail;
+    }
 
     wl_array_init(&stream_attribs);
     xwl_pixmap->buffer =