[Intel-gfx] [PATCH v3 1/5] drm/i915: Decouple cdclk calculation from modeset checks

[Ville Syrjälä]

On Mon, Mar 30, 2020 at 03:23:50PM +0300, Stanislav Lisovskiy wrote:
> We need to calculate cdclk after watermarks/ddb has been calculated
> as with recent hw CDCLK needs to be adjusted accordingly to DBuf
> requirements, which is not possible with current code organization.
> 
> Setting CDCLK according to DBuf BW requirements and not just rejecting
> if it doesn't satisfy BW requirements, will allow us to save power when
> it is possible and gain additional bandwidth when it's needed - i.e
> boosting both our power management and perfomance capabilities.
> 
> This patch is preparation for that, first we now extract modeset
> calculation from modeset checks, in order to call it after wm/ddb
> has been calculated.
> 
> v2: - Extract only intel_modeset_calc_cdclk from intel_modeset_checks
>       (Ville Syrjälä)
> 
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 7c45d676c9b7..17d83f37f49f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -14545,10 +14545,6 @@ static int intel_modeset_checks(struct intel_atomic_state *state)
>  			return ret;
>  	}
>  
> -	ret = intel_modeset_calc_cdclk(state);
> -	if (ret)
> -		return ret;
> -
>  	intel_modeset_clear_plls(state);
>  
>  	if (IS_HASWELL(dev_priv))
> @@ -14882,10 +14878,6 @@ static int intel_atomic_check(struct drm_device *dev,
>  			goto fail;
>  	}
>  
> -	ret = intel_atomic_check_crtcs(state);
> -	if (ret)
> -		goto fail;
> -
>  	intel_fbc_choose_crtc(dev_priv, state);
>  	ret = calc_watermark_data(state);
>  	if (ret)
> @@ -14895,6 +14887,16 @@ static int intel_atomic_check(struct drm_device *dev,
>  	if (ret)
>  		goto fail;
>  
> +	if (any_ms) {
> +		ret = intel_modeset_calc_cdclk(state);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = intel_atomic_check_crtcs(state);
> +	if (ret)
> +		goto fail;

I was thinking we'd do this as two patches. One with just the
extraction, and another one with the bigger reordering. But I think I
convinced myself that it should be safe, so maybe a single patch is
fine.

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> +
>  	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
>  					    new_crtc_state, i) {
>  		if (!needs_modeset(new_crtc_state) &&
> -- 
> 2.24.1.485.gad05a3d8e5

-- 
Ville Syrjälä
Intel