Re: [Intel-gfx] [PATCH] drm/i915: Implement a bit of bw_state readout

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

On Fri, Jun 17, 2022 at 07:07:30PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> We currently fail to reconstruct the bw related cdclk limits
> during readout, which triggers a  cdclk reclaculation during
> fastboot, which is then likely forces a full modeset anyway.
> Reconstruct some of the missing state so that we can skip
> the cdclk recomputation and thus have a higher chance for
> flicker free boot.

Problem is that intel_bw_min_cdclk is using intel_bw_dbuf_min_cdclk,
which in turns relies that bw_state->dbuf_bw was already calculated,
however this is calculated in intel_bw_calc_min_cdclk, which is called
from intel_cdclk_atomic_check.

So wondering will that work?

Stan

> 
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bw.c      | 9 ++++++---
>  drivers/gpu/drm/i915/display/intel_display.c | 7 +++++--
>  2 files changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c
> index 79269d2c476b..30ffec63f9a3 100644
> --- a/drivers/gpu/drm/i915/display/intel_bw.c
> +++ b/drivers/gpu/drm/i915/display/intel_bw.c
> @@ -627,11 +627,14 @@ void intel_bw_crtc_update(struct intel_bw_state *bw_state,
>  		intel_bw_crtc_data_rate(crtc_state);
>  	bw_state->num_active_planes[crtc->pipe] =
>  		intel_bw_crtc_num_active_planes(crtc_state);
> +	bw_state->min_cdclk[crtc->pipe] =
> +		intel_bw_crtc_min_cdclk(crtc_state);
>  
> -	drm_dbg_kms(&i915->drm, "pipe %c data rate %u num active planes %u\n",
> -		    pipe_name(crtc->pipe),
> +	drm_dbg_kms(&i915->drm, "[CRTC:%d:%s] data rate %u num active planes %u min cdclk %d kHz\n",
> +		    crtc->base.base.id, crtc->base.name,
>  		    bw_state->data_rate[crtc->pipe],
> -		    bw_state->num_active_planes[crtc->pipe]);
> +		    bw_state->num_active_planes[crtc->pipe],
> +		    bw_state->min_cdclk[crtc->pipe]);
>  }
>  
>  static unsigned int intel_bw_num_active_planes(struct drm_i915_private *dev_priv,
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 90bd26431e31..b17b9493c68f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2498,6 +2498,7 @@ static void intel_crtc_disable_noatomic(struct intel_crtc *crtc,
>  
>  	bw_state->data_rate[pipe] = 0;
>  	bw_state->num_active_planes[pipe] = 0;
> +	bw_state->min_cdclk[pipe] = 0;
>  }
>  
>  /*
> @@ -9310,6 +9311,8 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  		to_intel_cdclk_state(dev_priv->cdclk.obj.state);
>  	struct intel_dbuf_state *dbuf_state =
>  		to_intel_dbuf_state(dev_priv->dbuf.obj.state);
> +	struct intel_bw_state *bw_state =
> +		to_intel_bw_state(dev_priv->bw_obj.state);
>  	enum pipe pipe;
>  	struct intel_crtc *crtc;
>  	struct intel_encoder *encoder;
> @@ -9425,8 +9428,6 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  	drm_connector_list_iter_end(&conn_iter);
>  
>  	for_each_intel_crtc(dev, crtc) {
> -		struct intel_bw_state *bw_state =
> -			to_intel_bw_state(dev_priv->bw_obj.state);
>  		struct intel_crtc_state *crtc_state =
>  			to_intel_crtc_state(crtc->base.state);
>  		struct intel_plane *plane;
> @@ -9490,6 +9491,8 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  
>  		intel_bw_crtc_update(bw_state, crtc_state);
>  	}
> +
> +	cdclk_state->bw_min_cdclk = intel_bw_min_cdclk(dev_priv, bw_state);
>  }
>  
>  static void
> -- 
> 2.35.1
>