AHCI_PREG_CMD_SUD
cmd |= AHCI_PREG_CMD_SUD | AHCI_PREG_CMD_POD;
cmd &= ~AHCI_PREG_CMD_SUD;
AHCI_PREG_CMD_SUD |
cmd |= AHCI_PREG_CMD_POD | AHCI_PREG_CMD_SUD;
cmd |= AHCI_PREG_CMD_POD | AHCI_PREG_CMD_SUD;