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

[Kandpal, Suraj]

drm/i915/display: Increase AUX timeout
> for Type-C
> 
> On Mon, 17 Apr 2023, "Kandpal, Suraj" <suraj.kandpal at intel.com> wrote:
> >> -----Original Message-----
> >> From: Jani Nikula <jani.nikula at linux.intel.com>
> >> Sent: Monday, April 17, 2023 4:04 PM
> >> To: Kandpal, Suraj <suraj.kandpal at intel.com>; intel-
> >> gfx at 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 at intel.com> wrote:
> >> >> 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.
> >>
> >> 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?

I did think of that but the idea of disturbing other functions stopped me.
If that doesn't seem like an issue I could do that.

Regards,
Suraj Kandpal
> 
> 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