View Full Version : help Initializing DMA for faster DVD playback

02-20-2003, 06:58 PM
I found on http://www.knoppix.net/docs/index.php/FaqUsing

how to turn on the DMA so that the DVD could playback faster.
it works incredibly pretty smooth.

However I dont want to have to type in

/sbin/hdparm -d 1 /dev/hdc

as root every time I want to watch a DVD.

the article mentions putting the command into a startup


....I don't have /etc/initab on my system

Can someone walk me through the steps.

1. Exactly which start up script should I put this command into

2. What command should I put in? ( the article says to use /sbin/hdparm -d 1
but that doesn't seem right, wouldnt using /sbin/hdparm -d 1 /dev/hdc
in the script be correct?

please help.

PS Ive found this forum to be definitly one of the better ones for help. Keep up the great work!!![/b]

02-20-2003, 09:48 PM
I'm really sorry. I wrote the dvd howto and I made a spelling error. You should make the additions not to /etc/initab but to /etc/inittab.

I've fixed the howto. Hopefully this should work. Thanks for finding the mistake!

02-20-2003, 10:02 PM
Thank you for the update,

what about the actual command?

should it be

/sbin/hdparm -d 1 /dev/hdc


/sbin/hdparm -d 1

02-20-2003, 11:11 PM
It should be the first one:

/sbin/hdparm -d 1 /dev/hdc

When you reboot use /sbin/hdparm -d /dev/hdc to check make sure it enabled dma.

This should work. Please post back results.


02-21-2003, 12:13 AM
Nope it didnt work

here are the first lines of my /etc/inittab
# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.9 2001/05/31 10:37:50 knopper Exp $

# The default runlevel.

/sbin/hdparm -d 1 /dev/hdc

# Boot-time system configuration/initialization script.
# This is run first except when booting in emergency (-b) mode.

Also on boot up I notice there is a message saying something that
line 7 in etc/inittab is too long only 4 characters are allowed.

Line 7 is the /sbin/hdparm -d 1 /dev/hdc command.

After I logged in I did /sbin/hdparm -d /dev/hdc

here are the results

luis@Sphinux:~$ /sbin/hdparm -d /dev/hdc

using_dma = 0 (off)

but if I type in the command in root it makes the changes

any other ideas?

02-21-2003, 12:21 AM
I found this on a page about debian on thinkpads

In order to get decent playback performance out of the DVD drive, I ran: hdparm -d 1
/dev/hdc and also put this in a startup script:

# dmadvd - enable dma transfer on cd/dvd
# 2002-12-30,jtk

case $1 in

echo "Enabling DMA on CD/DVD drive..."
hdparm -d 1 /dev/hdc

echo "Disabling DMA on CD/DVD drive..."
hdparm -d 0 /dev/hdc

echo "Usage: $0 {start|stop}"
exit 1

exit 0

any idea which startup script I should put this into?

02-22-2003, 07:49 PM
I take it you're running a hd install. Save the DVD startup script in /etc/init.d as DVD.sh (or ???) then chmod it executable, then make a startup link in rc5.d to the DVD script in /etc/init.d:

ln -s /etc/init.d/DVD.sh /etc/rc5.d/S99DVD

then the DVD hdparm script will be loaded when you start in runlevel 5 near the end of the startup.

(Make sure to use the proper device, that your DVD is /dev/hdc)



02-22-2003, 08:24 PM
The settings for turning on DMA are at the bottom of the /etc/init.d/bootmisc.sh script at least on my system just uncomment the line for the DVD device or add a new one if is not there. BTW the proper syntax is hdparm -d1 no space between.

02-25-2003, 10:21 AM
Thank you so much,

your suggestion about /etc/init.d/bootmisc.sh worked perfectly!!!

dma is autoloaded now.

thanks again

02-27-2003, 08:39 PM
Thanks for the feedback. I've changed the howto and given /etc/init.d/bootmisc.sh as an example of where to enable dma for one's dvd.