[Nouveau] Does the (NV50) dma engine have trouble with "hammering"?

[Maarten Maathuis]

On Sat, Dec 27, 2008 at 2:35 AM, Maarten Maathuis <madman2003 at gmail.com> wrote:
> I'm doing some testing/coding on the ng branches and i've run into
> some problems, namely that i get PROTECTION_ERRORS after some time. It
> seems most common when two two dma's happen very close together on the
> same piece of memory (no hard proof to back this up, just something i
> noticed). I'm using the dma engine quite heavily and i've pretty much
> narrowed it down to that. I'm wondering if anyone has ever had such
> problems or knows of some special sync that is needed for m2mf. I'm
> doing copy, map, unmap, copy back for pretty much everything. About 10
> secs of gtkperf is enough to trigger it. I've gone as far as placing
> an NVSync after every dma transfer.

I should note (in hinsight) that a lot of closely spaced dma transfers
occur on the same piece of memory.

>
> I'd appreciate any kind of hint.
>
> Maarten.
>