Re: [Intel-gfx] [PATCH 16/23] drm/i915/mtl: Update memory bandwidth parameters

[Matt Roper <matthew.d.roper@intel.com>]

On Wed, Jul 27, 2022 at 06:34:13PM -0700, Radhakrishna Sripada wrote:
> Like ADL_P, Meteorlake has different memory characteristics from
> past platforms. Update the values used by our memory bandwidth
> calculations accordingly.
> 
> Bspec: 64631
> 
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Cc: Caz Yokoyama <caz.yokoyama@intel.com>
> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bw.c | 42 ++++++++++++++++++++++---
>  1 file changed, 38 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c
> index 8bbf47da1716..447a15f2c18a 100644
> --- a/drivers/gpu/drm/i915/display/intel_bw.c
> +++ b/drivers/gpu/drm/i915/display/intel_bw.c
> @@ -178,7 +178,32 @@ static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
>  	qi->num_points = dram_info->num_qgv_points;
>  	qi->num_psf_points = dram_info->num_psf_gv_points;
>  
> -	if (DISPLAY_VER(dev_priv) >= 12)
> +	if (DISPLAY_VER(dev_priv) >= 14) {
> +		switch (dram_info->type) {
> +		case INTEL_DRAM_DDR4:
> +			qi->t_bl = 4;
> +			qi->max_numchannels = 2;
> +			qi->channel_width = 64;
> +			qi->deinterleave = 2;
> +			break;
> +		case INTEL_DRAM_DDR5:
> +			qi->t_bl = 8;
> +			qi->max_numchannels = 4;
> +			qi->channel_width = 32;
> +			qi->deinterleave = 2;
> +			break;
> +		case INTEL_DRAM_LPDDR4:
> +		case INTEL_DRAM_LPDDR5:
> +			qi->t_bl = 16;
> +			qi->max_numchannels = 8;
> +			qi->channel_width = 16;
> +			qi->deinterleave = 4;
> +			break;
> +		default:
> +			MISSING_CASE(dram_info->type);
> +			return -EINVAL;
> +		}
> +	} else if (DISPLAY_VER(dev_priv) >= 12) {
>  		switch (dram_info->type) {
>  		case INTEL_DRAM_DDR4:
>  			qi->t_bl = is_y_tile ? 8 : 4;
> @@ -212,7 +237,7 @@ static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
>  			qi->max_numchannels = 1;
>  			break;
>  		}
> -	else if (DISPLAY_VER(dev_priv) == 11) {
> +	} else if (DISPLAY_VER(dev_priv) == 11) {
>  		qi->t_bl = dev_priv->dram_info.type == INTEL_DRAM_DDR4 ? 4 : 8;
>  		qi->max_numchannels = 1;
>  	}
> @@ -311,6 +336,13 @@ static const struct intel_sa_info adlp_sa_info = {
>  	.derating = 20,
>  };
>  
> +static const struct intel_sa_info mtl_sa_info = {
> +	.deburst = 32,
> +	.deprogbwlimit = 38, /* GB/s */
> +	.displayrtids = 256,
> +	.derating = 20,
> +};
> +
>  static int icl_get_bw_info(struct drm_i915_private *dev_priv, const struct intel_sa_info *sa)
>  {
>  	struct intel_qgv_info qi = {};
> @@ -585,9 +617,11 @@ void intel_bw_init_hw(struct drm_i915_private *dev_priv)
>  	if (!HAS_DISPLAY(dev_priv))
>  		return;
>  
> -	if (IS_DG2(dev_priv))
> +	if (DISPLAY_VER(dev_priv) >= 14)
> +		tgl_get_bw_info(dev_priv, &mtl_sa_info);
> +	else if (IS_DG2(dev_priv))
>  		dg2_get_bw_info(dev_priv);
> -	else if (DISPLAY_VER(dev_priv) >= 13 || IS_ALDERLAKE_P(dev_priv))
> +	else if (IS_ALDERLAKE_P(dev_priv))

Here you're undoing the change from the previous patch.  If you drop the
unwanted change from the previous patch and rebase the real changes here
accordingly,

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

>  		tgl_get_bw_info(dev_priv, &adlp_sa_info);
>  	else if (IS_ALDERLAKE_S(dev_priv))
>  		tgl_get_bw_info(dev_priv, &adls_sa_info);
> -- 
> 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation