DMA with current 2.4.x kernels

[François Jacques]

* Ralph Siemsen <ralphs at netwinder.org> [2005-04-11 10:17:42 -0400]:

> Andrew E. Mileski wrote:
> >François Jacques wrote:
> >
> >>Hi folks,
> >>
> >>Anyone has DMA enabled on /dev/had, under Linux 2.4.27 (debian sarge
> >>candidate kernel), on rev5 hardware? This config has the SL82C105
> >>rev5/SouthBridge rev10 combo, which supports DMA.
> >
> >It works great if you don't use the Tulip or play sound.
> >
> >There is a problem with the arbiter in the Windbond 553/554.
> >Basically there is only 1 usable DMA channel.
> 
> Agreed.  I haven't tried with 2.4.27 to be honest - kind of got stuck at 
> 2.4.19 for no particular reason other than time, but I have a good dozen 
> netwinders of various vintages and some of them do run in DMA mode (with 
> noticable performance boost on the disk).

ARGH. It has to work here too then!!

Are you using both the Tulip and NE2000 NICs?

> If you cannot get it working with the Debian kernel, please give a try 
> with my 2.4.19 binaries, if that changes your situation, we'll need to 
> review any kernel patches for differences.

Yippee. I wouldn't mind going back to 2.4.19, if ReiserFS was stable on that
version. Well, I could try booting from the network with 2.4.19, mounting
/boot only and then try to enable DMA on the hard disk along with the NICs. 

Thanks folks for the help.

-- 
François Jacques