DMA no active on HL-DT-STCD-RW/DVD

[Angka H. K.]

This is the result of this command :

angka# atacontrol mode acd0 wmda2
current mode = PIO4
angka# atacontrol mode acd0 wmda2
current mode = PIO4
angka#


On 5/13/06, Dmitry Pryanishnikov <dmitry at atlantis.dp.ua> wrote:
>
> Hello!
>
> On Sat, 13 May 2006, Angka H. K. wrote:
> > By the way what is WDMA and why it saying PIO not WDMA ?
>
>   WDMA corresponds to so-called "multiword DMA" transfer mode. It's slower than
> UDMA (IIRC WDMA2 gives 16Mbytes/s, same as PIO4), but still should be
> sufficient for CD/DVD drive (well, up to 8x-speed DVDs). Of course, it's
> better to use WDMA2 than PIO4 because WDMA (as well as UDMA) doesn't use
> CPU cycles for moving data between RAM and device. FreeBSD's ata driver
> is quite conservative, and doesn't automatically enable WDMA mode for
> ATAPI device even if hw.ata.atapi_dma=1, so you should just enable
> this mode with atacontrol. E.g., you can add
>
> /sbin/atacontrol mode acd0 wmda2
>
> to your /etc/rc.local file.
>
> Sincerely, Dmitry
> --
> Atlantis ISP, System Administrator
> e-mail:  dmitry at atlantis.dp.ua
> nic-hdl: LYNX-RIPE
>