memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
#ifdef CONFIG_ATA_SFF
- ap->ops->sff_tf_read(ap, &qc->tf);
+ if (ap->ops->sff_tf_read)
+ ap->ops->sff_tf_read(ap, &qc->tf);
#endif
/* fill these in, for the case where they are -not- overwritten */