HDIO_SET_DMA failed: Operation not permitted

[Andrew Bowden]

> On Fri, 2006-01-27 at 17:49 -0800, Biswajit Nayak wrote:
> > No I do not think i did with nodma . Here is the
> > output of 
> > 
> > [root at localhost ocsperf]# cat /proc/cmdline
> > ro root=/dev/VolGroup00/LogVol00 rhgb quiet
> 
> Ok, so you didn't disable DMA there.  You are, however, using LVM.
> Are you using hardware or software RAID?  If so, then you can't just
> turn DMA on on one drive, but on all drives that make up the RAID.
> 
> We also need to know a bit more about your hardware.  What motherboard
> are you using?  What kind of drives?
> 
> > 2. How to make sure that the controller/drive does not
> > permit dma 
> > ?
> 
> Again, it could be an interaction between RAID (if used), LVM and your
> controller.

Hi, I'm a long time reader, first time poster ;)
I think that I had this problem about a week ago when I was rebuilding
my kernel on a new Debian box.  It turned out that the problem was that
if you compiled the kernel with ide_generic enabled, this module
'knocked' off any specific ide controller (this was with kernel 2.6.12 -
I think).  

The way that I ended up fixing this was to do lspci and work out what
chipset was controlling the ide channel (from memory it was a VIA) and
then enabling this in the kernel and disabling the ide_generic module.

This worked for me, I am not guaranteeing anything for you - but if you
break it you get to keep both the pieces :)

Andrew Bowden