Re: [PATCH 1/2] drm/i915: Add a partial instruction shootdown workaround on Broadwell.

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Feb 26, 2014 at 11:59:30PM -0800, Kenneth Graunke wrote:
> I believe this will be necessary on production hardware.
> 
> Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 3 +++
>  drivers/gpu/drm/i915/intel_pm.c | 4 ++++
>  2 files changed, 7 insertions(+)
> 
> I just realized tonight that my workarounds series never got merged.
> 
> After reviewing Ben and Chris's comments, I agree with all of them, so
> I've dropped the unnecessary patches.  I also believe I shouldn't need
> the pre-production workarounds I sent last time, so I've dropped those.
> 
> These two should apply to production hardware, so we probably want them.
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index ad75ff7..f36d5e0 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5050,6 +5050,9 @@
>  #define   GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE	(1<<10)
>  #define   GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE	(1<<3)
>  
> +#define GEN8_ROW_CHICKEN		0xe4f0
> +#define   PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE	(1<<8)
> +
>  #define GEN7_ROW_CHICKEN2		0xe4f4
>  #define GEN7_ROW_CHICKEN2_GT2		0xf4f4
>  #define   DOP_CLOCK_GATING_DISABLE	(1<<0)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 4f01b04..df8ad21 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4838,6 +4838,10 @@ static void gen8_init_clock_gating(struct drm_device *dev)
>  	/* FIXME(BDW): Check all the w/a, some might only apply to
>  	 * pre-production hw. */
>  
> +	/* WaDisablePartialInstShootdown */

+:bdw

Apart from that:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> +	I915_WRITE(GEN8_ROW_CHICKEN,
> +	           _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE));
> +
>  	/*
>  	 * This GEN8_CENTROID_PIXEL_OPT_DIS W/A is only needed for
>  	 * pre-production hardware
> -- 
> 1.8.4.2
> 
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-- 
Ville Syrjälä
Intel OTC