Al-Husayn ibn Sa'id from Ibn Abi Umayr from Hafs from Abu Abdillah عليه السلام, peace be upon him, who said:
Imam al-Sadiq عليه السلام said: “He makes up the prayer during which he regained consciousness.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 3, p. 336