Re: [PATCH] drm/i915/skl: Implement WaBarrierPerformanceFixDisable (again)

[Ben Widawsky <ben@bwidawsk.net>]

On Wed, 03 Jun 2015 09:49:43 +0300
Jani Nikula <jani.nikula@linux.intel.com> wrote:

> On Wed, 03 Jun 2015, Ben Widawsky <benjamin.widawsky@intel.com> wrote:
> > in
> > commit 65ca7514e21adbee25b8175fc909759c735d00ff
> > Author: Damien Lespiau <damien.lespiau@intel.com>
> > Date:   Mon Feb 9 19:33:22 2015 +0000
> >
> >     drm/i915/skl: Implement WaBarrierPerformanceFixDisable
> >
> > The workaround ended up in the chv workarounds. Not sure what the
> > reason or history of that is, but it /seems/ wrong. Don't know if
> > this fixes anything since I have many other problems with my
> > platform.
> >
> > Cc: Damien Lespiau <damien.lespiau@intel.com>
> > Cc: Nick Hoath <nicholas.hoath@intel.com>
> > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> 
> Ville beat you to it [1]. However he put it in skl workarounds, not
> gen9, so I'm presuming this does not apply to bxt.
> 
> BR,
> Jani.
> 
> 

Anyone who will talk to us and tells you they know the answer to that
definitively is lying.

My patch is wrong though. Checking only the REVID without checking
IS_SKYLAKE is not the right thing to do.

Consider Ville's patch
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

(I no longer subscribe to intel-gfx, so actually adding my review is
kind of a pain).

> [1]
> http://mid.gmane.org/1433248657-4509-1-git-send-email-ville.syrjala@linux.intel.com
> 
> 
> > ---
> >  drivers/gpu/drm/i915/intel_ringbuffer.c | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > b/drivers/gpu/drm/i915/intel_ringbuffer.c index d934f85..0fd6033d
> > 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -901,13 +901,6 @@ static int chv_init_workarounds(struct
> > intel_engine_cs *ring) GEN6_WIZ_HASHING_MASK,
> >  			    GEN6_WIZ_HASHING_16x4);
> >  
> > -	if (INTEL_REVID(dev) == SKL_REVID_C0 ||
> > -	    INTEL_REVID(dev) == SKL_REVID_D0)
> > -		/* WaBarrierPerformanceFixDisable:skl */
> > -		WA_SET_BIT_MASKED(HDC_CHICKEN0,
> > -				  HDC_FENCE_DEST_SLM_DISABLE |
> > -				  HDC_BARRIER_PERFORMANCE_DISABLE);
> > -
> >  	return 0;
> >  }
> >  
> > @@ -972,6 +965,13 @@ static int gen9_init_workarounds(struct
> > intel_engine_cs *ring) tmp |=
> > HDC_FORCE_CSR_NON_COHERENT_OVR_DISABLE;
> > WA_SET_BIT_MASKED(HDC_CHICKEN0, tmp); 
> > +	if (INTEL_REVID(dev) == SKL_REVID_C0 ||
> > +	    INTEL_REVID(dev) == SKL_REVID_D0)
> > +		/* WaBarrierPerformanceFixDisable:skl */
> > +		WA_SET_BIT_MASKED(HDC_CHICKEN0,
> > +				  HDC_FENCE_DEST_SLM_DISABLE |
> > +				  HDC_BARRIER_PERFORMANCE_DISABLE);
> > +
> >  	return 0;
> >  }
> >  
> > -- 
> > 2.4.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 

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