PCIX_COMMAND_REGISTER
pci_read_config_word(hw->pdev, PCIX_COMMAND_REGISTER, &pcix_cmd_word);
pci_write_config_word(hw->pdev, PCIX_COMMAND_REGISTER, pcix_cmd_word);
e1000_read_pci_cfg(hw, PCIX_COMMAND_REGISTER, &pcix_cmd);
e1000_write_pci_cfg(hw, PCIX_COMMAND_REGISTER, &pcix_cmd);