hdparm question: HDIO_SET_DMA failed: Inappropriate ioctl for device

Jeff Spaleta jspaleta at gmail.com
Tue Nov 27 01:41:50 UTC 2007

On Nov 26, 2007 4:30 PM, Antonio Olivares <olivares14031 at yahoo.com> 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

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.


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