[Intel-gfx] [PATCH v2] drm/i915/display: Increase AUX timeout for Type-C

[Kandpal, Suraj]

> On Wed, 05 Apr 2023, Suraj Kandpal <suraj.kandpal at intel.com> wrote:
> > Type-C PHYs are taking longer than expected for Aux IO Power Enabling.
> > Workaround: Increase the timeout.
> >
> > WA_14017248603: adlp
> > Bspec: 55480
> >
> > ---v2
> > -change style on how we mention WA [Ankit] -fix bat error
> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >  .../i915/display/intel_display_power_well.c   | 30 ++++++++++++++++++-
> >  1 file changed, 29 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> > b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> > index 62bafcbc7937..52f595929a18 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> > @@ -489,6 +489,34 @@ static void icl_tc_cold_exit(struct
> drm_i915_private *i915)
> >  		    "succeeded");
> >  }
> >
> > +static void
> > +adl_aux_wait_for_power_well_enable(struct drm_i915_private *i915,
> > +				   struct i915_power_well *power_well,
> > +				   bool timeout_expected)
> > +{
> > +	const struct i915_power_well_regs *regs = power_well->desc->ops-
> >regs;
> > +	enum phy phy = icl_aux_pw_to_phy(i915, power_well);
> > +	int pw_idx = i915_power_well_instance(power_well)->hsw.idx;
> > +
> > +	/*
> > +	 * WA_14017248603: adlp
> > +	 * Type-C Phy are taking longer than expected for AUX IO Power
> Enabling.
> > +	 * Increase timeout to 500ms.
> > +	 */
> > +	if (IS_ALDERLAKE_P(i915) && intel_phy_is_tc(i915, phy)) {
> > +		if (intel_de_wait_for_set(i915, regs->driver,
> > +
> HSW_PWR_WELL_CTL_STATE(pw_idx), 500)) {
> > +			drm_dbg_kms(&i915->drm, "%s power well enable
> timeout\n",
> > +				    intel_power_well_name(power_well));
> > +
> > +			drm_WARN_ON(&i915->drm, !timeout_expected);
> > +		}
> > +		return;
> > +	}
> > +
> > +	hsw_wait_for_power_well_enable(i915, power_well,
> timeout_expected);
> > +}
> 
> Please don't duplicate the function and the wait like this.
> 
> Something like this is sufficient:
> 
> 
> @@ -252,7 +252,9 @@ static void hsw_wait_for_power_well_enable(struct
> drm_i915_private *dev_priv,
>  					   bool timeout_expected)
>  {
>  	const struct i915_power_well_regs *regs = power_well->desc->ops-
> >regs;
> +	enum phy phy = icl_aux_pw_to_phy(i915, power_well);
>  	int pw_idx = i915_power_well_instance(power_well)->hsw.idx;
> +	int timeout = 1;
> 
>  	/*
>  	 * For some power wells we're not supposed to watch the status bit
> for @@ -264,9 +266,13 @@ static void
> hsw_wait_for_power_well_enable(struct drm_i915_private *dev_priv,
>  		return;
>  	}
> 
> +	/* WA_14017248603: adlp */
> +	if (IS_ALDERLAKE_P(i915) && intel_phy_is_tc(i915, phy))

I did try this but it ends up throwing a kernel null pointer error at intel_phy_is_tc
which made me float the version of code I did.

Regards,
Suraj Kandpal
> +		timeout = 500;
> +
>  	/* Timeout for PW1:10 us, AUX:not specified, other PWs:20 us. */
>  	if (intel_de_wait_for_set(dev_priv, regs->driver,
> -				  HSW_PWR_WELL_CTL_STATE(pw_idx), 1)) {
> +				  HSW_PWR_WELL_CTL_STATE(pw_idx),
> timeout)) {
>  		drm_dbg_kms(&dev_priv->drm, "%s power well enable
> timeout\n",
>  			    intel_power_well_name(power_well));
> 
> 
> > +

> >  static void
> >  icl_tc_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
> >  				 struct i915_power_well *power_well) @@ -
> 517,7 +545,7 @@
> > icl_tc_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
> >  	if (DISPLAY_VER(dev_priv) == 11 &&
> intel_tc_cold_requires_aux_pw(dig_port))
> >  		icl_tc_cold_exit(dev_priv);
> >
> > -	hsw_wait_for_power_well_enable(dev_priv, power_well,
> timeout_expected);
> > +	adl_aux_wait_for_power_well_enable(dev_priv, power_well,
> > +timeout_expected);
> 
> A function prefixed adl_ should indicate it's only needed for adl+. This
> change is misleading.
> 
> BR,
> Jani.
> 
> 
> >
> >  	if (DISPLAY_VER(dev_priv) >= 12 && !is_tbt) {
> >  		enum tc_port tc_port;
> 
> --
> Jani Nikula, Intel Open Source Graphics Center