Linux 2.6.39-rc3

Joerg Roedel joro at
Thu Apr 14 23:50:17 PDT 2011

On Thu, Apr 14, 2011 at 05:34:46PM -0400, Alex Deucher wrote:
> On Thu, Apr 14, 2011 at 5:09 PM, Joerg Roedel <joro at> wrote:

> > Actually, the nb gart is part of the cpu. It is part of the cpu north
> > bridge and can translate io and cpu accesses. In fact, it is a remapper
> > of physical memory addresses.
> I know what it's for.  In the IGP graphics chip is also part of the
> north bridge, but it may not be related at all.

Okay, just wanted to make clear that it is part of the CPU and not of
the chipset :)

> > The problem seems to be related to specific gpu chips. On another
> > notebook with an hd3000 card gtt and the nb gart aperture are both on
> > 0xa0000000 too but the box works fine. I havn't tested with an hd5000
> > yet. The failing notebook has an hd4200 mobility.
> What exact model is the hd3000?   Is it IGP GPU or a discrete GPU?  It
> it's an IGP, it's identical to the hd4200 programming-wise.

It is an IGP card, an 

	"ATI Technologies Inc RS780M/RS780MN [Radeon HD 3200 Graphics]"

according to lspci.

> > Btw. what happens if the gpu accesses an unmapped address in the gtt
> > range?
> It's redirected to a dummy page.

So there should be no issue too, this is a very weird bug.


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