GDB server does not work in Windows

I build qemu with msys2, MINGW64. After fix the socket_error() problem, and manually specify to use IPv4, GDB server still does not work.  The related qemu command is
"-monitor none -nographic -gdb tcp::1234 -S"
GDB reports "Timed out"

There's a message at https://<email address hidden>/msg357981.html.
I've fixed the socket_error() problem.
I see that qio_channel_create_socket_watch is called.