Re: [PATCH 4/7] drm/i915: Disable SF pipelined attribute fetch for SNB

From: Kenneth Graunke <kenneth@whitecape.org>
To: ville.syrjala@linux.intel.com, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 4/7] drm/i915: Disable SF pipelined attribute fetch for SNB
Date: Fri, 07 Feb 2014 12:14:47 -0800	[thread overview]
Message-ID: <52F53EB7.9020001@whitecape.org> (raw)
In-Reply-To: <1391543961-1553-5-git-send-email-ville.syrjala@linux.intel.com>

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On 02/04/2014 11:59 AM, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> According to Bspec we need to disable SF pipelined attribute fetch
> whenever SF outputs exceed 16 and normal clip mode is used. A quick
> glance at Mesa suggests that these conditions could happen. So let's
> just always set the magic bit.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 3 ++-
>  drivers/gpu/drm/i915/intel_pm.c | 8 ++++++++
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 7aa2cf5..0334507 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -790,7 +790,8 @@
>  #define _3D_CHICKEN3	0x02090
>  #define  _3D_CHICKEN_SF_DISABLE_OBJEND_CULL		(1 << 10)
>  #define  _3D_CHICKEN3_SF_DISABLE_FASTCLIP_CULL		(1 << 5)
> -#define  _3D_CHICKEN_SDE_LIMIT_FIFO_POLY_DEPTH(x)	((x)<<1)
> +#define  _3D_CHICKEN_SDE_LIMIT_FIFO_POLY_DEPTH(x)	((x)<<1) /* gen8+ */
> +#define  _3D_CHICKEN3_SF_DISABLE_PIPELINED_ATTR_FETCH	(1 << 1) /* gen6 */
>  
>  #define MI_MODE		0x0209c
>  # define VS_TIMER_DISPATCH				(1 << 6)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 6a09281..7247084 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4683,6 +4683,14 @@ static void gen6_init_clock_gating(struct drm_device *dev)
>  		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_SF_DISABLE_FASTCLIP_CULL));
>  
>  	/*
> +	 * Bspec says:
> +	 * "This bit must be set if 3DSTATE_CLIP clip mode is set to normal and
> +	 * 3DSTATE_SF number of SF output attributes is more than 16."
> +	 */
> +	I915_WRITE(_3D_CHICKEN3,
> +		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_SF_DISABLE_PIPELINED_ATTR_FETCH));
> +
> +	/*
>  	 * According to the spec the following bits should be
>  	 * set in order to enable memory self-refresh and fbc:
>  	 * The bit21 and bit22 of 0x42000
> 

I'm almost positive Mesa will hit this case.  Nice catch!

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

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