Re: [PATCH] drm/i915/cnp: Wa 1181: Fix Backlight issue

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

On Tue, 29 Aug 2017, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> This workaround fixes a CNL PCH bug when changing
> backlight from a lower frequency to a higher frequency.
>
> During random reboot cycles, display backlight seems to
> be off/ dim for 2-3 mins.
>
> The only functional change on this patch is to
> set bit 13 of 0xC2020 for CNL PCH.
>
> The rest of patch is organizing identation around
> those bits definitions and re-organizing CFL workarounds.
>
> Cc: Arthur J Runyan <arthur.j.runyan@intel.com>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h | 11 ++++++-----
>  drivers/gpu/drm/i915/intel_pm.c | 27 +++++++++++++++++++++++++--
>  2 files changed, 31 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c59c590e45c4..31b1b1dfb754 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7474,11 +7474,12 @@ enum {
>  #define  FDI_RX_PHASE_SYNC_POINTER_EN	(1<<0)
>  #define FDI_RX_CHICKEN(pipe)	_MMIO_PIPE(pipe, _FDI_RXA_CHICKEN, _FDI_RXB_CHICKEN)
>  
> -#define SOUTH_DSPCLK_GATE_D	_MMIO(0xc2020)
> -#define  PCH_DPLUNIT_CLOCK_GATE_DISABLE (1<<30)
> -#define  PCH_DPLSUNIT_CLOCK_GATE_DISABLE (1<<29)
> -#define  PCH_CPUNIT_CLOCK_GATE_DISABLE (1<<14)
> -#define  PCH_LP_PARTITION_LEVEL_DISABLE  (1<<12)
> +#define SOUTH_DSPCLK_GATE_D			_MMIO(0xc2020)
> +#define  PCH_DPLUNIT_CLOCK_GATE_DISABLE		(1<<30)
> +#define  PCH_DPLSUNIT_CLOCK_GATE_DISABLE	(1<<29)
> +#define  PCH_CPUNIT_CLOCK_GATE_DISABLE		(1<<14)
> +#define  CNP_PWM_CGE_GATING_DISABLE		(1<<13)

Only add this one line, please don't reshuffle the rest.

> +#define  PCH_LP_PARTITION_LEVEL_DISABLE		(1<<12)
>  
>  /* CPU: FDI_TX */
>  #define _FDI_TXA_CTL            0x60100
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 88bbbc44c00d..5a4b41ea0c3a 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -8264,8 +8264,19 @@ static void gen8_set_l3sqc_credits(struct drm_i915_private *dev_priv,
>  	I915_WRITE(GEN7_MISCCPCTL, misccpctl);
>  }
>  
> +static void cnp_init_clock_gating(struct drm_i915_private *dev_priv)
> +{
> +	if (!HAS_PCH_CNP(dev_priv))
> +		return;

Is this for CFL without CNP?

BR,
Jani.

> +
> +	/* Wa #1181 */
> +	I915_WRITE(SOUTH_DSPCLK_GATE_D, CNP_PWM_CGE_GATING_DISABLE);
> +}
> +
>  static void cannonlake_init_clock_gating(struct drm_i915_private *dev_priv)
>  {
> +	cnp_init_clock_gating(dev_priv);
> +
>  	/* This is not an Wa. Enable for better image quality */
>  	I915_WRITE(_3D_CHICKEN3,
>  		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_AA_LINE_QUALITY_FIX_ENABLE));
> @@ -8285,6 +8296,16 @@ static void cannonlake_init_clock_gating(struct drm_i915_private *dev_priv)
>  			   SARBUNIT_CLKGATE_DIS);
>  }
>  
> +static void coffeelake_init_clock_gating(struct drm_i915_private *dev_priv)
> +{
> +	cnp_init_clock_gating(dev_priv);
> +	gen9_init_clock_gating(dev_priv);
> +
> +	/* WaFbcNukeOnHostModify:cfl */
> +	I915_WRITE(ILK_DPFC_CHICKEN, I915_READ(ILK_DPFC_CHICKEN) |
> +		   ILK_DPFC_NUKE_ON_ANY_MODIFICATION);
> +}
> +
>  static void kabylake_init_clock_gating(struct drm_i915_private *dev_priv)
>  {
>  	gen9_init_clock_gating(dev_priv);
> @@ -8299,7 +8320,7 @@ static void kabylake_init_clock_gating(struct drm_i915_private *dev_priv)
>  		I915_WRITE(GEN6_UCGCTL1, I915_READ(GEN6_UCGCTL1) |
>  			   GEN6_GAMUNIT_CLOCK_GATE_DISABLE);
>  
> -	/* WaFbcNukeOnHostModify:kbl,cfl */
> +	/* WaFbcNukeOnHostModify:kbl */
>  	I915_WRITE(ILK_DPFC_CHICKEN, I915_READ(ILK_DPFC_CHICKEN) |
>  		   ILK_DPFC_NUKE_ON_ANY_MODIFICATION);
>  }
> @@ -8767,9 +8788,11 @@ void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
>  {
>  	if (IS_CANNONLAKE(dev_priv))
>  		dev_priv->display.init_clock_gating = cannonlake_init_clock_gating;
> +	else if (IS_COFFEELAKE(dev_priv))
> +		dev_priv->display.init_clock_gating = coffeelake_init_clock_gating;
>  	else if (IS_SKYLAKE(dev_priv))
>  		dev_priv->display.init_clock_gating = skylake_init_clock_gating;
> -	else if (IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv))
> +	else if (IS_KABYLAKE(dev_priv))
>  		dev_priv->display.init_clock_gating = kabylake_init_clock_gating;
>  	else if (IS_BROXTON(dev_priv))
>  		dev_priv->display.init_clock_gating = bxt_init_clock_gating;

-- 
Jani Nikula, Intel Open Source Technology Center
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