364b813321
Return failure, if the enable bit corresponding to the map type has not been set in the command register. This feature was requested by Justin Gibbs, who pointed out that some early PCI to PCI bridges do not correctly support memory windows (I assume because of the risk of deadlocks that have been taken care of in the PCI 2.2 spec) and that some BIOS clears the memory address decode enable bit in the command register of the PCI device, if it finds them behind such a bridge.