BBC Sport golf correspondent Iain Carter analyses the controversy of Rory McIlroy's "non-conforming" driver at the 107th US PGA.

Rory McIlroy did not speak with the media at the PGA Championship, as news surfaced that his driver had been flagged by the USGA.

Kerry Haigh, the chief officer for championships in the PGA, pointed out that the USGA does not want to get involved in whose driver is not in accordance with the rules.