This has been a problem in the past (from what google tells me). But seems it was fixed sometime around unity 2017. I test linux about once a year, so here I find myself.... Anyway, before I log a bug into the abyss, I'm curious if anyone else has encountered this issue. 2018.2.17 and 2018.2.20 tested. Set Cursor.lockState = CursorLockMode.Locked. Now call Input.GetAxis("Mouse X"). You don't get back 0.1, or 0.5, or 1, you get back 3000, or more. Set Cursor.lockState = CursorLockMode.None (or Confined). Call Input.GetAxis("Mouse X"). You get back 0.1, 0.2, etc. as expected. Only happens on Linux (I tested using Ubuntu 18). Windows and Mac OS are fine. Only happens when the cursor is locked (as one is apt to do for implementing a mouse driven camera look).