[Mesa-dev] [PATCH] radeonsi: fix Hyper-Z hangs on P2 configs

[Marek Olšák]

On Wed, Mar 16, 2016 at 12:05 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> If I understand your patch correctly, the only effect is that a larger HTILE
> buffer is allocated, right? I'm surprised that only hangs were reported and
> not VM faults. We should really introduce guard pages / gaps between mapped
> buffers.

Yes, a larger HTILE is allocated.

VM faults aren't reported for out-of-bounds access within a page. My
theory is that the DB simply reads garbage data and hangs.

I'm not sure if 64KB pages are used for all VRAM allocations or only
big ones. 4KB pages should show VM faults, because the HTILE size is
always a multiple of (2KB * num_pipes), so it's 8KB at least. 64KB
pages can hide them.

>
> It seems like htile.{pitch, height, xalign, yalign} are never used (outside
> of some debug printing). I think it's a good idea to remove them (in a
> separate patch of course).

I added those only because of the debug printing. I'd like to know the
values when I'm debugging such stuff.

Marek