[Intel-gfx] [PATCH 07/26] drm/i915: implement WaDisablePSDDualDispatchEnable on VLV

[Jesse Barnes]

On Wed, 6 Mar 2013 20:20:21 +0200
Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:

> On Fri, Mar 01, 2013 at 02:08:23PM -0800, Jesse Barnes wrote:
> > Can prevent a hang when we get to tessellation.
> > 
> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c |    4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 61fee7f..59ea12a 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -3899,8 +3899,10 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
> >  		   CHICKEN3_DGMG_REQ_OUT_FIX_DISABLE |
> >  		   CHICKEN3_DGMG_DONE_FIX_DISABLE);
> >  
> > +	/* WaDisablePSDDualDispatchEnable */
> >  	I915_WRITE(GEN7_HALF_SLICE_CHICKEN1,
> > -		   _MASKED_BIT_ENABLE(GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE));
> > +		   _MASKED_BIT_ENABLE(GEN7_MAX_PS_THREAD_DEP |
> > +				      GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE));
> 
> The comment added matches what we already did. But the thread dep stuff
> seems to be something else. It seems to match the default value anyway,
> so shouldn't be needed AFAICS.

Hm not sure if we can trust the defaults with all the various BIOSes
out there. I'll have to check the workaround and see if the other bit
is needed (seems like it might be).

-- 
Jesse Barnes, Intel Open Source Technology Center