DMA will not turn on

Kobnar · #1 18th May 2006, 04:42 PM

I've been trying to play DVD's and such in FC5 but it's laggy as all hell. DMA is turned off on the device and I'm pretty sure that's why it lags so much.

I tried running:

Code:

/sbin/hdparm -d 1 /dev/hdc

but unning hdparm only returns:

Code:

/dev/hdc:
 setting using_dma to 1 (on)
 HDIO_SET_DMA failed: Operation not permitted
 using_dma    =  0 (off)
[root@localhost Kobnar]# gedit /etc/rc.d/rc.local

Note: I did hdc because "df" shows me that my DVD device is /dev/hdc/ (probibly has somthing to do with the fact that my computer is a Thinkpad and the CD/DVD drive is connected by an internal hot-swap USB port)

Does anyone know how I could turn DMA on?
Any help would be appreciated.
Thx.

Kobnar · #2 20th May 2006, 07:10 PM

c'mon... someone

olenb · #3 20th May 2006, 07:19 PM

I wonder if selinux is enabled and stopped this somehow?

Set USE_DMA = 1 in /etc/sysconfig/harddisks. Comment out a line, and see if that enables dma for
you. I think it may not work, since that just controls the same hdparm argument that you are setting.

Also I would try the hdparm command with and without a disk in the drive, and may with and without it being mounted when a disk is in the drive, to see if it changes anything.