Enabling DMA for atapi cd/dvd/rw

[JD]

# hdparm -d1 /dev/sr0

/dev/sr0:
  setting using_dma to 1 (on)
  HDIO_SET_DMA failed: Inappropriate ioctl for device
  HDIO_GET_DMA failed: Inappropriate ioctl for device

So, could someone please advise how to enable DMA
for the cd/dvd/rw drive?

It would sure help my aging laptop to play high quality
1080p HD movies.

PS: Keep in mind that ide-scsi emulation is used on all
       modern linux kernels since way back ????

[Alan Cox]

On Fri, 19 Oct 2012 15:13:32 -0600
JD  wrote:
> # hdparm -d1 /dev/sr0
>
> /dev/sr0:
>   setting using_dma to 1 (on)
>   HDIO_SET_DMA failed: Inappropriate ioctl for device
>   HDIO_GET_DMA failed: Inappropriate ioctl for device
>
> So, could someone please advise how to enable DMA
> for the cd/dvd/rw drive?
>
> It would sure help my aging laptop to play high quality
> 1080p HD movies.
>
> PS: Keep in mind that ide-scsi emulation is used on all
>        modern linux kernels since way back ????

The old IDE layer is obsolete and just kept around for a few legacy users
who don't want to switch. The current ATA code will always enable ATAPI
DMA when it is supported.