Share your experience!
Sometimes the vibration in my Xperia P LT22i doesn't work.
It happens without changing of settings. Slightly shaking of phone resolves the problem.
Also button feedback vibration may cause of continuous vibration (up to 1 second).
Is it possible to change vibration module?
What is the prospects of solving problem?
Try to repair your phone with SUS or PCC.
if problem is still there go to the nearest sony service center.