The intra-cluster medium (ICM) residing at the core of galaxy clusters is prone to radiative losses, and shoud cool to low temperatures. Yet, observations at all wave lengths fail to detect the expected large amounts of cold matter, showing that cooling must be balanced by some heating mechanism. There is general agreement that the AGN nested at the cluster's core plays a key role in keeping the ICM warm, and that this heating process must be stabilised by some kind of feedback. In this talk I review the 'cold feedback' mechanism, in which the mass accreted by the AGN originates in non-linear over-dense clumps of gas residing in an extended region (r 5 30 kpc); these clumps are originally hot, but then cool faster than their environment and sink toward the centre. As they are accreted by the AGN, they feed its activity, and hence the ICM heating. Since the mass accretion rate is determined by the ICM cooling time, the ICM entropy profile, and the presence of inhomogeneities, the AGN activity powers a self-regulated ICM heating. I argue that the cold feedback mechanism does not suffer the drawbacks that plague the more commonly adopted feedback mechanism based on the Bondi accretion on the AGN.