Fix deadlock in flush_wayland_fd() when using Wayland Vulkan driver (#18161)

Author: white-axe

input/common/wayland_common.c

@@ -1163,23 +1163,33 @@ void flush_wayland_fd(void *data)
    struct pollfd fd             = {0};
    input_ctx_wayland_data_t *wl = (input_ctx_wayland_data_t*)data;
 
-   wl_display_dispatch_pending(wl->dpy);
-   wl_display_flush(wl->dpy);
-
    fd.fd                        = wl->fd;
    fd.events                    = POLLIN | POLLOUT | POLLERR | POLLHUP;
 
+   while (wl_display_prepare_read(wl->dpy))
+      wl_display_dispatch_pending(wl->dpy);
+
+   wl_display_flush(wl->dpy);
+
    if (poll(&fd, 1, 0) > 0)
    {
-      if (fd.revents & (POLLERR | POLLHUP))
+      if (fd.revents & POLLIN)
       {
-         close(wl->fd);
-         frontend_driver_set_signal_handler_state(1);
+         wl_display_read_events(wl->dpy);
+         wl_display_dispatch_pending(wl->dpy);
       }
+      else
+         wl_display_cancel_read(wl->dpy);
 
-      if (fd.revents & POLLIN)
-         wl_display_dispatch(wl->dpy);
       if (fd.revents & POLLOUT)
          wl_display_flush(wl->dpy);
+
+      if (fd.revents & (POLLERR | POLLHUP))
+      {
+         close(wl->fd);
+         frontend_driver_set_signal_handler_state(1);
+      }
    }
+   else
+      wl_display_cancel_read(wl->dpy);
 }