Rules for barding performance states that:
Starting a bardic performance is a standard action, but it can be maintained each round as a free action. A bardic performance cannot be disrupted, but it ends immediately if the bard is killed, paralyzed, stunned, knocked unconscious, or otherwise prevented from taking a free action to maintain it each round.
Question: Let`s say bard engaged into battle, while using "Bardic performance". If he recieves damage, should player roll some check (like concentration for spellcasters)?