Re: [Intel-gfx] [PATCH 04/26] drm/i915: Reassign DPLLs only for crtcs going throug .compute_config()

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 03 May 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Only reassign the pipe's DPLL if it's going through a full
> .compute_config() cycle. If OTOH it's just getting modeset
> eg. in order to change cdclk there doesn't seem much point in
> picking a new DPLL for it.
>
> This should also prevent .get_dplls() from seeing a funky port_clock
> for DP even in cases where the readout produces a non-standard
> clock and we (for some reason) have decided to not fully recompute
> the state to remedy the situation.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

A bit unsure if I can appreciate all the subtleties here, but

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 17 +----------------
>  drivers/gpu/drm/i915/display/intel_dpll.c    |  6 ++----
>  2 files changed, 3 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 5e50e0d56088..7d488d320762 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -6955,20 +6955,6 @@ intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state)
>  	}
>  }
>  
> -static void intel_modeset_clear_plls(struct intel_atomic_state *state)
> -{
> -	struct intel_crtc_state *new_crtc_state;
> -	struct intel_crtc *crtc;
> -	int i;
> -
> -	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> -		if (!intel_crtc_needs_modeset(new_crtc_state))
> -			continue;
> -
> -		intel_release_shared_dplls(state, crtc);
> -	}
> -}
> -
>  /*
>   * This implements the workaround described in the "notes" section of the mode
>   * set sequence documentation. When going from no pipes or single pipe to
> @@ -7802,6 +7788,7 @@ static int intel_atomic_check(struct drm_device *dev,
>  			if (ret)
>  				goto fail;
>  
> +			intel_release_shared_dplls(state, crtc);
>  			continue;
>  		}
>  
> @@ -7849,8 +7836,6 @@ static int intel_atomic_check(struct drm_device *dev,
>  		ret = intel_modeset_calc_cdclk(state);
>  		if (ret)
>  			return ret;
> -
> -		intel_modeset_clear_plls(state);
>  	}
>  
>  	ret = intel_atomic_check_crtcs(state);
> diff --git a/drivers/gpu/drm/i915/display/intel_dpll.c b/drivers/gpu/drm/i915/display/intel_dpll.c
> index 2b3f72550e5a..afd30c6cc34c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpll.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpll.c
> @@ -1436,11 +1436,9 @@ int intel_dpll_crtc_get_shared_dpll(struct intel_atomic_state *state,
>  	int ret;
>  
>  	drm_WARN_ON(&i915->drm, !intel_crtc_needs_modeset(crtc_state));
> +	drm_WARN_ON(&i915->drm, !crtc_state->hw.enable && crtc_state->shared_dpll);
>  
> -	if (drm_WARN_ON(&i915->drm, crtc_state->shared_dpll))
> -		return 0;
> -
> -	if (!crtc_state->hw.enable)
> +	if (!crtc_state->hw.enable || crtc_state->shared_dpll)
>  		return 0;
>  
>  	if (!i915->dpll_funcs->crtc_get_shared_dpll)

-- 
Jani Nikula, Intel Open Source Graphics Center