Weird problem with IDE DMA and software RAID.

Luke Yelavich themuso at
Wed Jun 1 05:38:16 UTC 2005

Hi all

I have recently set up an Ubuntu Hoary installation using a secondary 
controller that my motherboard provides, which is a Promise controller. 
I am using two disks connected to this controller, as individual disks, 
but have installed Ubuntu on both using Software RAID 0. I have also got 
another hard disk connected to my primary master IDE port on the 
motherboard, and the DVD-ROM on secondary master.

The install went fine, however I cannot activate DMA on either the 
DVD-ROM or hard disk connected to my motherboard's standard IDE ports. I 
am using an 80-wire cable for the hard drive, and a 40-wire cable, 
capable of UDMA 2 for the DVD-ROM drive.

Running "sudo hdparm -d /dev/hda" and "sudo hdparm -d /dev/hdc" states 
that both drives are not using DMA on boot-up, which is expected for the 
DVD-ROM drive on hdc. However, when attempting to turn DMA on, using 
"sudo hdparm -d 1 /dev/hda" and hdc respectively, I get the following 
HDIO_SET_DMA failed: Operation not permitted.

What makes the whole situation even more weird, is when I run the live 
CD, the hard disk has DMA turned on at boot, as it should. Both drives 
also appear to be operating using DMA under windows as well 
on the same machine.

Suggestions welcome.
Luke Yelavich
GPG key: 0xD06320CE 
Email & MSN: themuso at
ICQ: 18444344
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <>

More information about the ubuntu-users mailing list