AHCI_TFD_ERR
ata_c->r_error = AHCI_TFD_ERR(tfd);
if (AHCI_TFD_ERR(tfd) & WDCS_DWF) {
ata_bio->r_error = AHCI_TFD_ERR(tfd);
sc_xfer->sense.atapi_sense = AHCI_TFD_ERR(tfd);