On Nov 26, 2007 4:30 PM, Antonio Olivares <olivares14031@xxxxxxxxx> wrote: > If one enables hdparm DVD playback will not be jumpy, however when applying hdparm I get Perhaps the libata faq will give you the most basic answer http://linux-ata.org/faq.html#old_ioctls Now are you sure that the drive isn't already using dma by default? hdparm -i /dev/cdrom will list the supported DMA modes and will indicate which one is currently in use. By default my DVD drive has the most advanced DMA enabled by default DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 mdma2 UDMA modes: udma0 udma1 *udma2 * signifies the current active mode As to why hdparm is attempting to use the legacy ioctls, that I have no idea. -jef