How to enable DMA on IDE CD/DVD drives connected to SATA

[kirk]

I've got a Dell Latitude D610 that has a SATA harddrive and an IDE CD/DVD IDE drive. Problem is that DMA is not enabled on the CD/DVD drive by default and you can't enable it with hdparm. This leads to choppy DVD playback with Gxine and overall crappy CD/DVD performance. I found this solution that works and thought I'd post it here.

1) Add the following line to the end of /etc/modprobe.conf
(leaving an extra empty line behind it):

options libata atapi_enabled=1


2) Then add this parameter to /boot/grub/menu.lst

combined_mode=libata

Mine looks like this:

title Puppy 2.16 (on /dev/sda4)
rootnoverify(hd0,3)
kernel (hd0,3)/boot/216f/vmlinuz root=/dev/ram0 combined_mode=libata PMEDIA=satahd
initrd (hd0,3)/boot/216f/initrd.gz

3) Reboot.

Now your DVD drive should be called "/dev/scd0"


4) Symlink /dev/scd0 to /dev/cdrom and /dev/dvd.

Now Gine should work!

4.5) Reverse the above steps if everthing is hosed up.

[kirk]

Found out Step 1 posted above is not necessary. Also Dougal pointed out that /dev/sr0 is also the dvd drive.