[Intel-gfx] [PATCH 06/22] drm/i915: add power context allocation and setup on VLV

[Jesse Barnes]

On Tue, 5 Feb 2013 20:01:15 +0200
Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:

> On Sat, Feb 02, 2013 at 01:56:10PM +0100, Jesse Barnes wrote:
> > The Gunit has a separate reg for this, so allocate some stolen space for
> > the power context and initialize the reg.
> 
> AFAIK the BIOS is responsible for setting up the PCBR register. The
> register can also be locked preventing further updates, so if the BIOS
> actually has done what it's supposed to, this code will fail.
> 
> So should we just instead read out the PCBR and remove the range from
> the stolen mem pool?

At the very least.  I'll have to check with the BIOS folks; I'm pretty
sure on some machines we'll need to do this ourselves.

Jesse