AHCI_PREG_SACT
mask |= ahci_pread(ap, AHCI_PREG_SACT);
ahci_pwrite(ap, AHCI_PREG_SACT, mask);
ahci_pwrite(ap, AHCI_PREG_SACT, mask);
ci_saved = ahci_pread(ap, AHCI_PREG_SACT);
ap->ap_sactive, ahci_pread(ap, AHCI_PREG_SACT));
sact = ahci_pread(ap, AHCI_PREG_SACT);
sact = ahci_pread(ap, AHCI_PREG_SACT);
ahci_pread(ap, AHCI_PREG_SACT),
ci_saved = (ap->ap_sactive) ? ahci_pread(ap, AHCI_PREG_SACT) :
ahci_pwrite(ap, AHCI_PREG_SACT, ci_saved);
ahci_pwrite(ap, AHCI_PREG_SACT, (1 << i));