[vox-tech] enabling DMA on cd/dvd combo drive

[Rob Rogers]

On Thu, Mar 13, 2003 at 14:39:07PM -0800, Ryan wrote:
> as requested:
> 
> $ls -l /dev/cdrom
> lrwxrwxrwx    1 root     root            9 Mar  7 10:06 /dev/cdrom ->
> /dev/scd0

There's the problem. hdparm only likes IDE devices, and /dev/cdrom is
pointing to a SCSI device.

> $dmesg | grep hd
> Kernel command line: ro root=LABEL=/ hdc=ide-scsi
> ide_setup: hdc=ide-scsi
>     ide0: BM-DMA at 0xf000-0xf007, BIOS settings: hda:DMA, hdb:pio
>     ide1: BM-DMA at 0xf008-0xf00f, BIOS settings: hdc:DMA, hdd:pio
> hda: WDC WD800JB-00CRA1, ATA DISK drive
> hdc: SAMSUNG CDRW/DVD SM-332B, ATAPI CD/DVD-ROM drive
> hda: 156301488 sectors (80026 MB) w/8192KiB Cache, CHS=9729/255/63,
> UDMA(100)
>  hda: hda1 hda2 hda3 hda4 < hda5 >

hdparm -d1 /dev/hdc should work. At least it won't give you an error.
Not actually positive if it will do anything (haven't tested here, but
I've got a similar setup and it doesn't give the error it does on
/dev/cdrom)