ixp4xx dmabounce

[Mikael Pettersson]

Brian Walsh wrote:
> > =C2=A0> I tried Krzysztof's patch and it had no noticeable affect. =C2=A0=
> I am still getting
> > =C2=A0> about 6.3 Mbps IP data throughput when only using the ohci contro=
> ller and
> > =C2=A0> about 3.6 Mbps when the device is attached to the ehci controller=
> . =C2=A0This
> > =C2=A0> device works fine when running the same testing attached to an x8=
> 6
> > =C2=A0> configured machine and gets about 18 Mbps IP data throughput.
> >
> > If your application can operate in 64MB RAM, you may want to try
> > a kernel that includes only my ixp4xx disable dmabounce patch,
> > and boot it with mem=3D64M. (Look in the kernel boot log and verify
> > that it only sees 64M of RAM.)
> >
> > If performance increases, then your performance loss is due to bounces.
> >
> 
> Mikael
> 
> I used your patch to disable legacy bounce, disabled support for > 64MB RAM=
> ,
> and used the mem=3D64M kernel option.  There was no change in the data
> throughput.
> 
> I am not sure where this leaves me.

To me it implies that the performance issues are unrelated to
your initial bouncing issues. Since you get better performance
from OHCI I'd have to suspect a hardware or driver issue with
your EHCI controller.