Patgom145

Hello everybody, I am discovering Atari Emulation on PC (and it is harder than I thought) and it is very nice to rediscover my childhood pleasures. The first two systems I tries to emulate are Atari 2600 through Retroarch (Stella core) and Atari 5200 through Retroarch (atari800 core) or Kat5200. For both systems I managed to set up my roms and my emulators and to play 99% of the games BUT I can't play 2 players games as my second controller does not have any effect. For instance for Fall Down or Combat in Atari 2600 or Joust in Atari 5200 I can manage to play 1 player game but not 2 players which makes me mad. In Combat it is even worse as my 1st controller makes move the 2 tanks... What is strange is that both my controllers are detected when I launch the games : My controllers are Ibuffalo Classic USB Gamepad which are "classic" as I think. I have spend my two last evening trying to understand what I am missing but I have no more idea. Many thanks for any help. Patgom145