# trying to enable DMA and getting error

## niyogi

I'm getting the following error when trying to use hdparm to enable DMA:

HDIO_SET_DMA failed: Operation not permitted 

Any ideas how to get past this?  Thanks in advance!

-S

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## metalhedd

I've had a ton of problems trying to get DMA Working on my drives too.  what ide controller is on your motherboard? have yo enabled the right driver in the kernel? also try upgrading your kernel to 2.4.19pre5 or higher, the IDE Code is apparently much improved in this version.  I can't remember the exact errors I was getting but it can also be caused by having an IDE Cable longer than 18" (I had one and didn't even know till i tried every other option!)

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## niyogi

hmm... could it be because you have the cd rom drive and the hard drive on the same cable?

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## metalhedd

That was also one of the things I was told, is that it looked like my cd burner was causing the problems (one of the errors messages I was getting was referring to my burner when I was only trying to enable DMA on the Hard Drive)  but I ruled this out because i have used the drive under linux before and burned cd's perfectly with it at 12x and had DMA Enabled fine.  The Very first thing to try and the one thing that I would target first is the kernel, either compiling the right drivers or upgrading to 2.4.19-pre5+

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