Re: [Intel-gfx] [PATCH v2 2/5] drm/i915/display/dg2: Sanitize CD clock

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Fri, Nov 19, 2021 at 03:13:45PM +0200, Mika Kahola wrote:
> In case of CD clock squashing the divider is always 1. We don't
> need to calculate the divider in use so let's skip that for DG2.
> 
> v2: Drop unnecessary local variable (Ville)
> v3: Avoid if-else structure (Ville)
> [v4: vsyrjala: Fix cd2x divider calculation (Uma),
>                Introduce has_cdclk_squasher()]
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 7af4cb965060..3a61d52bdc0e 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1212,6 +1212,11 @@ static void skl_cdclk_uninit_hw(struct drm_i915_private *dev_priv)
>  	skl_set_cdclk(dev_priv, &cdclk_config, INVALID_PIPE);
>  }
>  
> +static bool has_cdclk_squasher(struct drm_i915_private *i915)
> +{
> +	return IS_DG2(i915);
> +}
> +
>  static const struct intel_cdclk_vals bxt_cdclk_table[] = {
>  	{ .refclk = 19200, .cdclk = 144000, .divider = 8, .ratio = 60 },
>  	{ .refclk = 19200, .cdclk = 288000, .divider = 4, .ratio = 60 },
> @@ -1735,7 +1740,7 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
>  static void bxt_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  {
>  	u32 cdctl, expected;
> -	int cdclk, vco;
> +	int cdclk, clock, vco;
>  
>  	intel_update_cdclk(dev_priv);
>  	intel_dump_cdclk_config(&dev_priv->cdclk.hw, "Current CDCLK");
> @@ -1771,8 +1776,12 @@ static void bxt_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  	expected = skl_cdclk_decimal(cdclk);
>  
>  	/* Figure out what CD2X divider we should be using for this cdclk */
> -	expected |= bxt_cdclk_cd2x_div_sel(dev_priv,
> -					   dev_priv->cdclk.hw.cdclk,
> +	if (has_cdclk_squasher(dev_priv))
> +		clock = dev_priv->cdclk.hw.vco / 2;
> +	else
> +		clock = dev_priv->cdclk.hw.cdclk;
> +
> +	expected |= bxt_cdclk_cd2x_div_sel(dev_priv, clock,
>  					   dev_priv->cdclk.hw.vco);
>  
>  	/*
> -- 
> 2.27.0
>