Re: [PATCH] drm/i915: unconditionally use mt forcewake on hsw/ivb

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Oct 19, 2012 at 09:39:59AM -0700, Jesse Barnes wrote:
> On Thu, 18 Oct 2012 14:44:35 +0200
> Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> 
> > Single-threaded forcewake was only used on some early pre-production
> > ivybridge machines, all the latest ones should use mt forcewake. And
> > we already assume this in other places of the code (e.g. DERRMR
> > support in the ddx, or the latest intel_gt_reset patch to reset any
> > lingering forcewake references left behind by the bios), so don't
> > bother here, too.
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c |   31 ++++---------------------------
> >  1 file changed, 4 insertions(+), 27 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 2b3cddf..568c98d 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -4146,35 +4146,12 @@ void intel_gt_init(struct drm_device *dev)
> >  	if (IS_VALLEYVIEW(dev)) {
> >  		dev_priv->gt.force_wake_get = vlv_force_wake_get;
> >  		dev_priv->gt.force_wake_put = vlv_force_wake_put;
> > -	} else if (INTEL_INFO(dev)->gen >= 6) {
> > +	} else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
> > +		dev_priv->gt.force_wake_get = __gen6_gt_force_wake_mt_get;
> > +		dev_priv->gt.force_wake_put = __gen6_gt_force_wake_mt_put;
> > +	} else if (IS_GEN6(dev)) {
> >  		dev_priv->gt.force_wake_get = __gen6_gt_force_wake_get;
> >  		dev_priv->gt.force_wake_put = __gen6_gt_force_wake_put;
> > -
> > -		/* IVB configs may use multi-threaded forcewake */
> > -		if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
> > -			u32 ecobus;
> > -
> > -			/* A small trick here - if the bios hasn't configured
> > -			 * MT forcewake, and if the device is in RC6, then
> > -			 * force_wake_mt_get will not wake the device and the
> > -			 * ECOBUS read will return zero. Which will be
> > -			 * (correctly) interpreted by the test below as MT
> > -			 * forcewake being disabled.
> > -			 */
> > -			mutex_lock(&dev->struct_mutex);
> > -			__gen6_gt_force_wake_mt_get(dev_priv);
> > -			ecobus = I915_READ_NOTRACE(ECOBUS);
> > -			__gen6_gt_force_wake_mt_put(dev_priv);
> > -			mutex_unlock(&dev->struct_mutex);
> > -
> > -			if (ecobus & FORCEWAKE_MT_ENABLE) {
> > -				DRM_DEBUG_KMS("Using MT version of forcewake\n");
> > -				dev_priv->gt.force_wake_get =
> > -					__gen6_gt_force_wake_mt_get;
> > -				dev_priv->gt.force_wake_put =
> > -					__gen6_gt_force_wake_mt_put;
> > -			}
> > -		}
> >  	}
> >  }
> >  
> 
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Merged, thanks for checking. I've also merged the forcewak clear patch
from Chris, somehow forgotten to send the mail.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch