[Intel-gfx] [PATCH 2/2] drm/i915: Short-circuit no-op vga_set_state()

[Chris Wilson]

On Tue, Dec 17, 2013 at 11:45:45AM +0000, Chris Wilson wrote:
> On Tue, Dec 17, 2013 at 11:21:27AM +0200, Jani Nikula wrote:
> > On Mon, 16 Dec 2013, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > > Touching the VGA registers risks a hard machine hang, at least on this
> > > ivb machine after removing a conflicting efifb. This is more than likely
> > > related to the discovery that VGA IO decode on the more recent PCH
> > > platforms is terminally broken.
> > 
> > Please double check the config space address. At a glance, it looks like
> > we should be using SNB_GMCH_CTRL since SNB. Might explain the issues?
> 
> Hmm, indeed. This bit is at a different location on SNB, but it is
> locked. Which is where all the vgaarb madness began last time.

Ok, that feels at least as stable as not writing to the invalid address.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre