MACE DMA problem on Powermac 7300

[Risto Suominen]

Hi, Ben,

2009/12/7, Benjamin Herrenschmidt <benh at kernel.crashing.org>:
>
> Cache coherency bugs in the chipset or HW bugs in DBDMA, we've been
> seeing those on/off on those old apple chipsets...
>
> Try forcing a 32 bytes alignment ?
>
You're thinking of placing the DMA descriptors on different cache lines?

That's excactly what I did with de2104x. But it was easier, I think.
The chip handled its own DMA, and by writing a skip value to a
register... I don't know this GC DMA controller well enough and
haven't found the documentation either...

But I tried the de21041 board with unmodified driver on this 7300, and
it works. The problem was on a 5500.

Risto