Unable to enable DMA on some AMD systems

[Thomas Hofer]

Christoph Wiesen wrote: [Sunday 05 June 2005 15:05]
> sudo hdparm -d1 /dev/hd? gives me an error message:
>
> /dev/hdd:
>  setting using_dma to 1 (on)
>  HDIO_SET_DMA failed: Operation not permitted
>  using_dma    =  0 (off)
>
> This has happened to me before with other Debian systems.
>
> Previously the issue could have been 'solved' by compiling my own
> kernel where I'd include "amd74xx" in the kernel itself - not as a
> module. Even though I've owned a different system at that time*, the
> issue is the same and I'm sure re-compiling could help here.

I had the same problem with my Tyan Tiger MPX board. The culprit was the 
generic IDE kernel module, that was loaded by /etc/modules before the 
amd74xx module. (That's why compiling in helps, BTW)

My solution was to insert "amd74xx" as first line into /etc/modules and 
reboot.

I think commenting out the lines starting with ide- should also do the 
trick, but I'm not sure why those modules are there.

bye,
Thomas.