Does 'swap trick' only work for games which have 'swap trick' patches posted for the

[hrmmm]

I assume by swap trick it means u can play ps2 backups w/o a mod chip and a gameshark.....or is the swap trick something else u have to do IN ADDITION to having the modchip and gameshark.
In either case, does this swap trick work for ANY ps2 game or ONLY the games which have swap trick patches posted for them? tia for any help. =)