[Intel-gfx] [PATCH] drm/i915: Set up PIPE_MISC truncate bit on tgl+

[Souza, Jose]

On Wed, 2020-02-26 at 18:30 +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Looks like the pipe rounding mode bit has moved from PIPE_CHICKEN to
> PIPE_MISC on tgl. Frob the new location.
> 
> Bspec does still document the old bits as well, so I left the code
> for them as is until we get clarification from the hw folks on
> whether the old bits still do something useful.

Matches Bspec, please CC me in the future patch removing the old bit if
needed.

Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 3 +++
>  drivers/gpu/drm/i915/i915_reg.h              | 1 +
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index 2fd3ccd33e30..4e8744c15f4b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -10139,6 +10139,9 @@ static void bdw_set_pipemisc(const struct
> intel_crtc_state *crtc_state)
>  					   BIT(PLANE_CURSOR))) == 0)
>  		val |= PIPEMISC_HDR_MODE_PRECISION;
>  
> +	if (INTEL_GEN(dev_priv) >= 12)
> +		val |= PIPEMISC_PIXEL_ROUNDING_TRUNC;
> +
>  	intel_de_write(dev_priv, PIPEMISC(crtc->pipe), val);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h
> index f45b5e86ec63..133c48311649 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5889,6 +5889,7 @@ enum {
>  #define   PIPEMISC_YUV420_MODE_FULL_BLEND (1 << 26) /* glk+ */
>  #define   PIPEMISC_HDR_MODE_PRECISION	(1 << 23) /* icl+ */
>  #define   PIPEMISC_OUTPUT_COLORSPACE_YUV  (1 << 11)
> +#define   PIPEMISC_PIXEL_ROUNDING_TRUNC	REG_BIT(8) /* tgl+ */
>  #define   PIPEMISC_DITHER_BPC_MASK	(7 << 5)
>  #define   PIPEMISC_DITHER_8_BPC		(0 << 5)
>  #define   PIPEMISC_DITHER_10_BPC	(1 << 5)