[Intel-gfx] [PATCH v2] drm/i915:bxt: implement WaProgramL3SqcReg1DefaultForPerf

[Michel Thierry]

On 4/20/2016 3:23 PM, tim.gore at intel.com wrote:
> From: Tim Gore <tim.gore at intel.com>
>
> This patch applies a performance enhancement workaround
> based on analysis of DX and OCL S-Curve workloads.
>
> v2: Only apply to B0 onwards
>
> Signed-off-by: Tim Gore <tim.gore at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_reg.h | 1 +
>   drivers/gpu/drm/i915/intel_pm.c | 4 ++++
>   2 files changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index f0a6d85..13e154a 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6074,6 +6074,7 @@ enum skl_disp_power_wells {
>
>   #define GEN8_L3SQCREG1				_MMIO(0xB100)
>   #define  BDW_WA_L3SQCREG1_DEFAULT		0x784000
> +#define  BXT_WA_L3SQCREG1_DEFAULT		0xF84000
>
>   #define GEN7_L3CNTLREG1				_MMIO(0xB01C)
>   #define  GEN7_WA_FOR_GEN7_L3_CONTROL			0x3C47FF8C
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index b7c2186..eecdc3a6 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -76,6 +76,10 @@ static void bxt_init_clock_gating(struct drm_device *dev)
>   	if (IS_BXT_REVID(dev_priv, BXT_REVID_B0, REVID_FOREVER))
>   		I915_WRITE(GEN9_CLKGATE_DIS_0, I915_READ(GEN9_CLKGATE_DIS_0) |
>   			   PWM1_GATING_DIS | PWM2_GATING_DIS);
> +
> +	/* WaProgramL3SqcReg1DefaultForPerf:bxt */
> +	if (IS_BXT_REVID(dev, BXT_REVID_B0, REVID_FOREVER))
> +		I915_WRITE(GEN8_L3SQCREG1, BXT_WA_L3SQCREG1_DEFAULT);
>   }
>
>   static void i915_pineview_get_mem_freq(struct drm_device *dev)
>

Isnt it better to add this to bxt_init_workarounds() instead of 
bxt_init_clock_gating()?

And It doesnt hurt to put what it is doing in the commit msg, i.e.:
"Increasing GP credits to 62 (from default 56), and reducing HP credits 
to 2 (from default 8)"

-Michel