[Intel-gfx] [PATCH 4/4] drm/i915/cnl: Apply large line width optimization

[Oscar Mateo]

On 07/05/2017 06:02 PM, Rodrigo Vivi wrote:
> This bit enables hardware that will change the approximation used for distances
> calculations for AA wide lines so that they are rendered more accurately.
>
> The default value for this bit leaves the legacy behavior. There is no good
> reason to not enable the new approximation except if comparing to previous GEN
> rendered images.

Sounds reasonable :)

> v2: Rebase
>
> Signed-off-by: Ben Widawsky <benjamin.widawsky at intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_reg.h | 1 +
>   drivers/gpu/drm/i915/intel_pm.c | 3 +++
>   2 files changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 2999a2b..78af798 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2310,6 +2310,7 @@ enum skl_disp_power_wells {
>   # define _3D_CHICKEN2_WM_READ_PIPELINED			(1 << 14)
>   #define _3D_CHICKEN3	_MMIO(0x2090)
>   #define  _3D_CHICKEN_SF_DISABLE_OBJEND_CULL		(1 << 10)
> +#define  _3D_CHICKEN3_AA_LINE_QUALITY_FIX_ENABLE	(1 << 5)
>   #define  _3D_CHICKEN3_SF_DISABLE_FASTCLIP_CULL		(1 << 5)
>   #define  _3D_CHICKEN_SDE_LIMIT_FIFO_POLY_DEPTH(x)	((x)<<1) /* gen8+ */
>   #define  _3D_CHICKEN3_SF_DISABLE_PIPELINED_ATTR_FETCH	(1 << 1) /* gen6 */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index df1b608..5d5df2b 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -8230,6 +8230,9 @@ static void cannonlake_init_clock_gating(struct drm_i915_private *dev_priv)
>   {
>   	gen9_init_clock_gating(dev_priv);
>   
> +	I915_WRITE(_3D_CHICKEN3,
> +		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_AA_LINE_QUALITY_FIX_ENABLE));
> +

Maybe add the justification for this as a comment?

>   	/* WaFbcNukeOnHostModify:cnl */
>   	I915_WRITE(ILK_DPFC_CHICKEN, I915_READ(ILK_DPFC_CHICKEN) |
>   		   ILK_DPFC_NUKE_ON_ANY_MODIFICATION);