[Intel-gfx] [PATCH 09/10] drm/i915: flush system agent TLBs on SNB

[Daniel Vetter]

On Tue, Oct 23, 2012 at 07:17:53AM -0700, Jesse Barnes wrote:
> On Mon, 22 Oct 2012 18:34:14 -0700
> Ben Widawsky <ben at bwidawsk.net> wrote:
> 
> > This allows us to map the PTEs WC. I've not done thorough testing or
> > performance measurements with this patch, but it should be decent.
> > 
> > This is based on a patch from Jesse with the original commit message
> > > I've only lightly tested this so far, but the corruption seems to be
> > > gone if I write the GFX_FLSH_CNTL reg after binding an object.  This
> > > register should control the TLB for the system agent, which is what CPU
> > > mapped objects will go through.
> > 
> > It has been updated for the new AGP-less code by me, and included with
> > it is feedback from the original patch.
> > 
> > CC: Jesse Barnes <jbarnes at virtuousgeek.org>
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_gtt.c | 5 +++--
> >  drivers/gpu/drm/i915/i915_reg.h     | 2 ++
> >  2 files changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 16fe960..e5f0a7f 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -391,6 +391,7 @@ static void gen6_ggtt_bind_object(struct drm_i915_gem_object *obj,
> >  	}
> >  
> >  out:
> > +	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
> >  	/* XXX: This serves as a posting read preserving the way the old code
> >  	 * works. It's not clear if this is strictly necessary or just voodoo
> >  	 * based on what I've tried to gather from the docs.
> > @@ -593,8 +594,8 @@ int i915_gem_gtt_init(struct drm_device *dev)
> >  	if (ret)
> >  		return ret;
> >  
> > -	dev_priv->mm.gtt->gtt = ioremap(gtt_bus_addr,
> > -					dev_priv->mm.gtt->gtt_total_entries * sizeof(gtt_pte_t));
> > +	dev_priv->mm.gtt->gtt = ioremap_wc(gtt_bus_addr,
> > +					   dev_priv->mm.gtt->gtt_total_entries * sizeof(gtt_pte_t));
> >  
> >  	/* GMADR is the PCI aperture used by SW to access tiled GFX surfaces in a linear fashion. */
> >  	DRM_DEBUG_DRIVER("GMADR size = %dM\n", dev_priv->mm.gtt->gtt_mappable_entries >> 8);
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 1d54328..e8c578f 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -683,6 +683,8 @@
> >  #define   CM0_RC_OP_FLUSH_DISABLE (1<<0)
> >  #define BB_ADDR		0x02140 /* 8 bytes */
> >  #define GFX_FLSH_CNTL	0x02170 /* 915+ only */
> > +#define GFX_FLSH_CNTL_GEN6	0x101008
> > +#define   GFX_FLSH_CNTL_EN	(1<<0)
> >  #define ECOSKPD		0x021d0
> >  #define   ECO_GATING_CX_ONLY	(1<<3)
> >  #define   ECO_FLIP_DONE		(1<<0)
> 
> Looks good.  Has anyone tried this on gen3-5?

pre-gen6 still use the intel_gtt code, since we need to for the next
decade or so to keep ums (and crappy xvmc on gen3) going.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch