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 02:43:25PM +0300, Kandpal, Suraj wrote:
> > [...]
> > 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?

The HSD is for display 13 ADL, that is ADL-P/M/N. The ADL-S power wells
are described separately in adls_power_wells.

--Imre