Unable to enable DMA on some AMD systems

[Christoph Wiesen]

Hello everyone,

let me explain the issue I have that doesn'T allow me to use Kubuntu as much 
as I'd like;
Basically I do not have DMA enabled for my IDE devices and can't do so either.

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.

*Then I had an nForce2 Motherboard, now I have a MSI K8T Neo2 with a Via 
K8T800 Pro chipset.

Luckily I only have two IDE devices now - both DVD drives. My harddisks are 
SATA and working fine. So I've used Kubuntu happily for quite some time. Now 
I have to use the DVD drives a bit more and partly switched to another 
distribution, mostly for that reason.

There I do not have that issue. It's SuSE 9.3, which uses a 2.6.11 kernel and 
it's the x86_64 version.

Since this doesn't seem to be limited to me, I had the slight hope using the 
2.6.10-k7 kernel might fix it (maybe the module was included here), but it 
didn't. It's not very sensible to hope using the x86_64 version of Kubuntu 
will fix it, is it?

Is there any chance this might be solved with breezy? Maybe with the next 
Ubuntu 2.6.11? 

It wouldn't be sensible to ask for a solution here if this issue only affected 
me, but from what I can tell quite a few AMD users are affected - it seems 
rather common to just build your own kernel (including amd74xx in the kernel) 
and be done with it - so maybe it's a kernel bug.

So if it is I guess Kubuntu as a good desktop distro might want to provide a 
solution in the meantime like e.g. SuSE does.

I hope I've already included all the necessary information - if not, I'd be 
happy to provide more info. 

Here's a thread (in german) about the issue I had in debian - there are more 
issues later, but the basics seem the same:
http://www.debianforum.de/forum/viewtopic.php?t=36651&start=0&postdays=0&postorder=asc&highlight=



Kind regards,

Christoph Wiesen