Musannaf Ibn Abi Shayba 3:187

Abu Bakr narrated to us, he said: Abd al-Salam ibn al-Harith narrated to us, from Ishaq ibn Abd Allah ibn Abi Farwah, from Isma'il ibn Ubayd Allah, that he asked Abu Hurayrah and said: "I am a one-eyed man, so what should I say in the glorification (tasbih) during prostration?" He said: "Three glorifications."