DMA with current 2.4.x kernels

[Ralph Siemsen]

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).

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.

http://netwinder.osuosl.org/devteam/ralphs/kernel/

I can extract from the RPMS if necessary.

-Ralph