Listen, ill be real with you, its basically unusable and unreliable in most scenarios. The technical reason for this is due to Wayland vs X11 and other underdeveloped display technology. Normal gaming just got good enough after years of work. And before anyone tells me that the Index does work on Linux, it sure does just not well at all.
I have since sold my Index but when I used it, 80% of it was on windows. Be on the lookout for something called the Valve Deckard. I believe thats when Linux VR will finally be ready.