Re: [PATCH v3] drm/i915/icl: Fix clockgating issue when using scalers

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

On Thu, Mar 21, 2019 at 02:44:31PM -0700, Radhakrishna Sripada wrote:
> Fixes the clock-gating issue when pipe scaling is enabled.
> (Lineage #2006604312)
> 
> V2: Fix typo in headline(Chris)
>     Handle the non double buffered nature of the register(Ville)
> V3: Fix checkpatch warning. BAT failure for V2 on gen3 looks unrelated.
> 
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Aditya Swarup <aditya.swarup@intel.com>
> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 43 +++++++++++++++++-----------
>  1 file changed, 27 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 7c15b428ff84..cfa19ae12e22 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -469,13 +469,22 @@ static const struct intel_limit intel_limits_bxt = {
>  static void
>  skl_wa_clkgate(struct drm_i915_private *dev_priv, int pipe, bool enable)
>  {
> +	u32 val = 0;
> +
> +	/*
> +	 * Wa_2006604312:icl
> +	 */
> +	if (IS_ICELAKE(dev_priv))
> +		val = DPFR_GATING_DIS;
> +	else
> +		val = DUPS1_GATING_DIS | DUPS2_GATING_DIS;
> +
> +	/* WA Display #0827: Gen9:all */

You're now conflating two workaround and splitting their implementation
between two functions in a confusing way. Better to keep them separate
IMO.

>  	if (enable)
> -		I915_WRITE(CLKGATE_DIS_PSL(pipe),
> -			   DUPS1_GATING_DIS | DUPS2_GATING_DIS);
> +		I915_WRITE(CLKGATE_DIS_PSL(pipe), val);
>  	else
>  		I915_WRITE(CLKGATE_DIS_PSL(pipe),
> -			   I915_READ(CLKGATE_DIS_PSL(pipe)) &
> -			   ~(DUPS1_GATING_DIS | DUPS2_GATING_DIS));
> +			   I915_READ(CLKGATE_DIS_PSL(pipe)) & ~val);
>  }
>  
>  static bool
> @@ -5481,14 +5490,18 @@ static bool hsw_post_update_enable_ips(const struct intel_crtc_state *old_crtc_s
>  	return !old_crtc_state->ips_enabled;
>  }
>  
> -static bool needs_nv12_wa(struct drm_i915_private *dev_priv,
> -			  const struct intel_crtc_state *crtc_state)
> +static bool skl_needs_clk_wa(struct drm_i915_private *dev_priv,
> +			     const struct intel_crtc_state *crtc_state)
>  {
> -	if (!crtc_state->nv12_planes)
> -		return false;
> -
>  	/* WA Display #0827: Gen9:all */
> -	if (IS_GEN(dev_priv, 9) && !IS_GEMINILAKE(dev_priv))
> +	if (!!crtc_state->nv12_planes && IS_GEN(dev_priv, 9) &&
> +	    !IS_GEMINILAKE(dev_priv))
> +		return true;
> +
> +	/*
> +	 * Wa_2006604312:icl
> +	 */
> +	if (IS_ICELAKE(dev_priv) && crtc_state->pch_pfit.enabled)
>  		return true;
>  
>  	return false;
> @@ -5527,9 +5540,8 @@ static void intel_post_plane_update(struct intel_crtc_state *old_crtc_state)
>  			intel_post_enable_primary(&crtc->base, pipe_config);
>  	}
>  
> -	/* Display WA 827 */
> -	if (needs_nv12_wa(dev_priv, old_crtc_state) &&
> -	    !needs_nv12_wa(dev_priv, pipe_config)) {
> +	if (skl_needs_clk_wa(dev_priv, old_crtc_state) &&
> +	    !skl_needs_clk_wa(dev_priv, pipe_config)) {
>  		skl_wa_clkgate(dev_priv, crtc->pipe, false);
>  	}
>  }
> @@ -5566,9 +5578,8 @@ static void intel_pre_plane_update(struct intel_crtc_state *old_crtc_state,
>  			intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, false);
>  	}
>  
> -	/* Display WA 827 */
> -	if (!needs_nv12_wa(dev_priv, old_crtc_state) &&
> -	    needs_nv12_wa(dev_priv, pipe_config)) {
> +	if (!skl_needs_clk_wa(dev_priv, old_crtc_state) &&
> +	    skl_needs_clk_wa(dev_priv, pipe_config)) {
>  		skl_wa_clkgate(dev_priv, crtc->pipe, true);
>  	}
>  
> -- 
> 2.20.0.rc2.7.g965798d1f299

-- 
Ville Syrjälä
Intel
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