On 8 Oct 2002, Johan Andersson wrote:
> Hello list,
>
> I'm having trouble getting my dvd (Pioneer DVD-ROM ATAPI Model DVD-106S
> 012) to use dma. Whenever I try to set it (as root) I get:
>
> ---------------------------------------------
> # /sbin/hdparm -d1 /dev/hdc
>
> /dev/hdc:
> setting using_dma to 1 (on)
> HDIO_SET_DMA failed: Operation not permitted
> using_dma = 0 (off)
> ---------------------------------------------
>
> Could anyone explain to me how I could get it working? :-)
> Thanks in advance!
i don't think you can. from a previous posting, didn't someone mention
that red hat just flat out doesn't support DMA for some drives?
in any case, the source code for hdparm contains the conditional
if (ioctl(fd, HDIO_SET_DMA, dma))
perror("HDIO_SET_DMA failed") ;
if ioctl() can't make the change, i don't think there's any way
you can do it.
rday
