Check whether atapi dma can be supported
int atapi_check_dma(struct ata_queued_cmd * qc);
qc
Metadata associated with taskfile to check
Allow low-level driver to filter ATA PACKET commands, returning a status indicating whether or not it is OK to use DMA for the supplied PACKET command.
spin_lock_irqsave(host lock)
0 when ATAPI DMA can be used nonzero otherwise
Jeff Garzik
Author.