Re: libata - DMA problems ICH7 rev 02

[Robert Hancock]

Jan Niklas Hasse wrote:
> On Fri, May 2, 2008 at 2:58 PM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> > > my BIOS didn't support it), but none of them worked (every time my
> >  > harddisk is loading my CPU is spammed with IOWait).
> >
> >  Then you must have a different problem ?
>
> Maybe, but it seems as DMA isn't used. Everytime my hard disk is
> reading/writing my system gets very slow. Here's the line when i run
> top:
>
> Cpu(s): 12.6%us,  5.4%sy,  0.0%ni,  6.5%id, 74.2%wa,  0.5%hi,  0.8%si,  0.0%st
>
> The thing I mean is "wa".

This is expected. IOWait just means the system is blocked waiting for IO 
 and has nothing else to do. It does not mean that DMA is not working.

> >  > Output of uname -a and lspci is attached.
> >  >
> >  > I hope you can help me, very hard to work without DMA.
> >
> >  Please send the output of "dmesg" after boot
>
> Okay, I pasted it here: http://rafb.net/p/KiWhqE72.html

Looks like you are using DMA:

ata1.00: configured for UDMA/100
ata1.01: configured for UDMA/33
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