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

[Imre Deak <imre.deak@intel.com>]

On Mon, Apr 17, 2023 at 01:56:12PM +0300, Jani Nikula wrote:
> On Mon, 17 Apr 2023, "Kandpal, Suraj" <suraj.kandpal@intel.com> wrote:
> >> -----Original Message-----
> >> From: Jani Nikula <jani.nikula@linux.intel.com>
> >> Sent: Monday, April 17, 2023 4:04 PM
> >> To: Kandpal, Suraj <suraj.kandpal@intel.com>; intel-
> >> gfx@lists.freedesktop.org
> >> Subject: RE: [Intel-gfx] [PATCH v2] drm/i915/display: Increase AUX timeout
> >> for Type-C
> >> 
> >> On Mon, 17 Apr 2023, "Kandpal, Suraj" <suraj.kandpal@intel.com> wrote:
> >> >> On Wed, 05 Apr 2023, Suraj Kandpal <suraj.kandpal@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@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.
> >> 
> >> 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;
 };

 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