ok, this one is NOT posted as often anymore... I dont know if its because people have figured it out or what but I'm going to put in my 2 bits if for no other reason that I tend to forget and posting it here means I will be able to find it again later!

if you are a diehard linux lover or even if you are just getting into it... and you have hit that magical point where you decide you want to watch your DVD in xine. and if you have a motherboard with almost any intel sata enabled chipset, there is that wonderful dma check flicker problem... it is caused by DMA detection failure because your IDE deviced (your DVD drive) are running THROUGH the sata bus. this causes a problem for the kernel when detecting the ide devices which kills DMA.

and here is the resolution:

add this to the kernel peramter line in your /boot/grub/menu.lst file

this will make everything better. trust me. there is NOTHING else you have to do. no DMA enableing, no special drivers or kernel builds you need, just combined_mode=libata. it makes DMA play nicely.

here is an example from a debian isntall:

happy day...