Re: [PATCH] drm/i915/icl: apply Display WA #1178 to fix type C dongles

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Sep 24, 2018 at 09:54:35AM -0700, Lucas De Marchi wrote:
> Display WA #1178 is meant to fix Aux channel voltage swing too low with
> some type C dongles. Although it is for type C, of ICL it only applies
> to combo phy and not to eDP. This means we need to apply the WA only on
> Aux B.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h         | 4 ++++
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 7 +++++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index e7e6ca7f9665..1e92112d23de 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -8928,6 +8928,10 @@ enum skl_power_gate {
>  #define   CNL_AUX_ANAOVRD1_ENABLE	(1 << 16)
>  #define   CNL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 23)
>  
> +#define ICL_AUX_ANAOVRD1_B		_MMIO(0x6C398)
> +#define   ICL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 7)
> +#define   ICL_AUX_ANAOVRD1_ENABLE	(1 << 0)
> +
>  /* HDCP Key Registers */
>  #define HDCP_KEY_CONF			_MMIO(0x66c00)
>  #define  HDCP_AKSV_SEND_TRIGGER		BIT(31)
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 0fdabce647ab..a97d2f762b77 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -436,6 +436,13 @@ icl_combo_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
>  	I915_WRITE(ICL_PORT_CL_DW12(port), val | ICL_LANE_ENABLE_AUX);
>  
>  	hsw_wait_for_power_well_enable(dev_priv, power_well);
> +
> +	/* Display WA #1178: icl */
> +	if (IS_ICELAKE(dev_priv) && pw_idx == ICL_PW_CTL_IDX_AUX_B) {

Spec tells:
CNL: This programming does not apply to Aux A.
ILC: Aux A: Set 0x162398 bit 0 and bit 7 = 1
with extra note of This programming only applies for external ports on the combo PHY,
not on type C PHY, and not for eDP.

So I believe we need to add Aux A here and add a check for !is_edp

> +		val = I915_READ(ICL_AUX_ANAOVRD1_B);
> +		val |= ICL_AUX_ANAOVRD1_ENABLE | ICL_AUX_ANAOVRD1_LDO_BYPASS;
> +		I915_WRITE(ICL_AUX_ANAOVRD1_B, val);
> +	}
>  }
>  
>  static void
> -- 
> 2.17.1
> 
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