PCI_COMM_BACK2BACK_ENAB
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
comm |= PCI_COMM_BACK2BACK_ENAB;
comm |= PCI_COMM_BACK2BACK_ENAB;
comm |= PCI_COMM_BACK2BACK_ENAB;
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
PCI_COMM_BACK2BACK_ENAB |
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);
command &= (command_preserve | PCI_COMM_BACK2BACK_ENAB);