hdparm/dma
 

I am trying to enable dma on /dev/hdd.
I found a few threads that said that I will need to add a line to /etc/modules.conf file. Will the line be: options hdd dma=1 ?
I have no idea how to do this. I figured out how to change it from 16 bit to 32 bit though. hdd is a partition on my hard drive right? It wouldn't be a hard drive problem would it? It is an 80 gb two year old drive.

what said you want to edit modules.conf? shouldn't need to at all.

just use hdparm directly.

hdparm -k 1 -d 1 /dev/hda

-d = dma -k = keep settings on reboot

hdd would be your secondary slave drive, so that will be unlikely to be correct.

hda is already in 32 bit mode with dma turned on
when I do:
hdparm -d1 /dev/hdd

I get:
setting using_dma to 1 (on)
HDIO_set_dma failed:operation not permitted
Using _dma =0 (off)


However, this is good right, because if hda is 32 bit dma enabled then it is not a hardware problem, right?

you're not root i guess.... it'd be a very strange world if a normal user can enable dma on a drive...

no no,,,, that is logged out as normal user and logged in as root

O.K. hdd is not a partition of the hard drive. hdd is the dvd player. The line I needed to add to /etc/modules.conf is:
options hdc-cd dma=1

I figured out how to do this on my own.
But, when I did it my -Tt score went from 13.36MB/sec to 1.67MB/sec to INPUT/OUTPUT error. Then I tried xine again and it still plays(poorly) If I have got the thing so scrambled that it can't test itself how does it still play. I tried removing the line. xine-check says I have dma problems again. What is this input output error. How do I correct this?

Did you ever fix this because I'm exactly where you were at when you posted and no one's helping me.

Maybe DMA is not enabled in your kernel. I seem to recall some chipsets (especially VIA) need a special compile flag. Maybe:

CONFIG_BLK_DEV_VIA82CXXX=y

I think I was caught by this compiling kernel 2.4.21 on a VIA KT setup. There are also a bunch of flags affected DMA directly. I have

CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDEDMA_AUTO=y

Sorry if that is a bit vague. If you google 'HDIO_set_dma failed' you will see this is a not uncommon gotcha. Maybe there is some boot parameter to fix things??? Otherwise you probably have to recompile the kernel. Where did you get your kernel in the first place?

Later: the VIA82CXXX support is also available as a module, so you might be able to modprobe it: 'modprobe via82cxxx', if you think that might be the problem.