Re: [Intel-gfx] [PATCH v4 1/5] drm/i915: Decouple cdclk calculation from modeset checks

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Apr 07, 2020 at 10:33:56AM +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)
> 
> v3: - Clear plls after intel_modeset_calc_cdclk

Why did we change this now?

> 
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 22 +++++++++++---------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 70ec301fe6e3..c77088e1d033 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -14464,12 +14464,6 @@ 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))
>  		return hsw_mode_set_planes_workaround(state);
>  
> @@ -14801,10 +14795,6 @@ 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)
> @@ -14814,6 +14804,18 @@ 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;
> +
> +		intel_modeset_clear_plls(state);
> +	}
> +
> +	ret = intel_atomic_check_crtcs(state);
> +	if (ret)
> +		goto fail;
> +
>  	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
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