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

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> -----Original Message-----
> From: Deak, Imre <imre.deak@xxxxxxxxx>
> Sent: Monday, April 17, 2023 4:58 PM
> To: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>; intel-
> gfx@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  [PATCH v2] drm/i915/display: Increase AUX timeout
> for Type-C
> 
> On Mon, Apr 17, 2023 at 01:56:12PM +0300, Jani Nikula wrote:
> > On Mon, 17 Apr 2023, "Kandpal, Suraj" <suraj.kandpal@xxxxxxxxx> wrote:
> > >> -----Original Message-----
> > >> From: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> > >> Sent: Monday, April 17, 2023 4:04 PM
> > >> To: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>; intel-
> > >> gfx@xxxxxxxxxxxxxxxxxxxxx
> > >> Subject: RE:  [PATCH v2] drm/i915/display: Increase AUX
> > >> timeout for Type-C
> > >>
> > >> On Mon, 17 Apr 2023, "Kandpal, Suraj" <suraj.kandpal@xxxxxxxxx>
> wrote:
> > >> >> On Wed, 05 Apr 2023, Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> 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@xxxxxxxxx>
> > >> >> > ---
> > >> >> >  .../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.
> > >>
> > >> Please explain what causes it, and how your version avoids it.
> > >>
> > >
> > > icl_aux_pw_to_phy is called is hsw_wait_for_power_well is called
> > > everywhere where its not possible for aux_pw to phy conversion is not
> possible with this change we only get the phy for adls version.
> > > Will address this is next version.
> >
> > Cc: Imre for input
> >
> > Maybe pass the timeout to hsw_wait_for_power_well_enable() as
> parameter?
> > Other ideas?
> 
> Adding a non-default enable_timeout to the power well descriptor would
> avoid adding more platform checks:
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power_map.c
> b/drivers/gpu/drm/i915/display/intel_display_power_map.c
> index 6645eb1911d85..8ca1f34be14c2 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power_map.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power_map.c
> @@ -1378,13 +1378,18 @@ static const struct i915_power_well_desc
> xelpd_power_wells_main[] = {
>  			I915_PW("AUX_C", &icl_pwdoms_aux_c, .hsw.idx =
> ICL_PW_CTL_IDX_AUX_C),
>  			I915_PW("AUX_D", &icl_pwdoms_aux_d, .hsw.idx =
> XELPD_PW_CTL_IDX_AUX_D),
>  			I915_PW("AUX_E", &icl_pwdoms_aux_e, .hsw.idx =
> XELPD_PW_CTL_IDX_AUX_E),
> +		),
> +		.ops = &icl_aux_power_well_ops,
> +		.fixed_enable_delay = true,
> +	}, {
> +		.instances = &I915_PW_INSTANCES(
>  			I915_PW("AUX_USBC1", &tgl_pwdoms_aux_usbc1,
> .hsw.idx = TGL_PW_CTL_IDX_AUX_TC1),
>  			I915_PW("AUX_USBC2", &tgl_pwdoms_aux_usbc2,
> .hsw.idx = TGL_PW_CTL_IDX_AUX_TC2),
>  			I915_PW("AUX_USBC3", &tgl_pwdoms_aux_usbc3,
> .hsw.idx = TGL_PW_CTL_IDX_AUX_TC3),
>  			I915_PW("AUX_USBC4", &tgl_pwdoms_aux_usbc4,
> .hsw.idx = TGL_PW_CTL_IDX_AUX_TC4),
>  		),
>  		.ops = &icl_aux_power_well_ops,
> -		.fixed_enable_delay = true,
> +		.enable_timeout = 500,
>  	}, {
>  		.instances = &I915_PW_INSTANCES(
>  			I915_PW("AUX_TBT1", &icl_pwdoms_aux_tbt1,
> .hsw.idx = TGL_PW_CTL_IDX_AUX_TBT1), 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 62bafcbc7937c..930a42c825c36 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> @@ -253,6 +253,7 @@ static void hsw_wait_for_power_well_enable(struct
> drm_i915_private *dev_priv,  {
>  	const struct i915_power_well_regs *regs = power_well->desc->ops-
> >regs;
>  	int pw_idx = i915_power_well_instance(power_well)->hsw.idx;
> +	int timeout = power_well->desc->enable_timeout ? : 1;
> 
>  	/*
>  	 * For some power wells we're not supposed to watch the status bit
> for @@ -266,7 +267,7 @@ static void
> hsw_wait_for_power_well_enable(struct drm_i915_private *dev_priv,
> 
>  	/* 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));
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.h
> b/drivers/gpu/drm/i915/display/intel_display_power_well.h
> index ba7cb977e7c7f..fd5acf68503e1 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power_well.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.h
> @@ -110,6 +110,8 @@ struct i915_power_well_desc {
>  	 * Thunderbolt mode.
>  	 */
>  	u16 is_tc_tbt:1;
> +	/* Enable timeout if bigger than the default 1ms. */
> +	u16 enable_timeout;
>  };
> 

How would we make sure that this timeout only applies to ADLS in that case as that's whom the workaround is for?

Regards,
Suraj Kandpal
>  struct i915_power_well {
> 
> > BR,
> > Jani.
> >
> > >
> > > Regards,
> > > Suraj Kandpal
> > >> BR,
> > >> Jani.
> > >>
> > >>
> > >> >
> > >> > 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
> > >>
> > >> --
> > >> Jani Nikula, Intel Open Source Graphics Center
> >
> > --
> > Jani Nikula, Intel Open Source Graphics Center




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