Re: [Intel-gfx] [PATCH 2/2] drm/i915/pps: Enable 2nd pps for dual EDP scenario

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 16 Sep 2022, "Manna, Animesh" <animesh.manna@intel.com> wrote:
>> -----Original Message-----
>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Sent: Friday, September 16, 2022 2:28 PM
>> To: Manna, Animesh <animesh.manna@intel.com>
>> Cc: intel-gfx@lists.freedesktop.org; Nikula, Jani <jani.nikula@intel.com>;
>> Shankar, Uma <uma.shankar@intel.com>
>> Subject: Re: [PATCH 2/2] drm/i915/pps: Enable 2nd pps for dual EDP scenario
>>
>> On Fri, Sep 16, 2022 at 02:01:02PM +0530, Animesh Manna wrote:
>> > >From display gen12 onwards to support dual EDP two instances of pps added.
>> > Currently backlight controller and pps instance can be mapped together
>> > for a specific panel. Extended support for gen12 for dual EDP usage.
>> >
>> > v1: Iniital revision
>> > v2: Called intel_bios_panel_init w/o PNPID before intel_pps_init.
>> > [Jani]
>> >
>> > Cc: Jani Nikula <jani.nikula@intel.com>
>> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> > Cc: Uma Shankar <uma.shankar@intel.com>
>> > Signed-off-by: Animesh Manna <animesh.manna@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_bios.c | 7 -------
>> > drivers/gpu/drm/i915/display/intel_bios.h | 7 +++++++
>> >  drivers/gpu/drm/i915/display/intel_dp.c   | 9 ++++++---
>> >  drivers/gpu/drm/i915/display/intel_pps.c  | 2 +-
>> >  4 files changed, 14 insertions(+), 11 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c
>> > b/drivers/gpu/drm/i915/display/intel_bios.c
>> > index 28bdb936cd1f..5fd4c09dfa96 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_bios.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c
>> > @@ -706,13 +706,6 @@ static int fallback_get_panel_type(struct
>> drm_i915_private *i915,
>> >     return 0;
>> >  }
>> >
>> > -enum panel_type {
>> > -   PANEL_TYPE_OPREGION,
>> > -   PANEL_TYPE_VBT,
>> > -   PANEL_TYPE_PNPID,
>> > -   PANEL_TYPE_FALLBACK,
>> > -};
>> > -
>> >  static int get_panel_type(struct drm_i915_private *i915,
>> >                       const struct intel_bios_encoder_data *devdata,
>> >                       const struct edid *edid)
>> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.h
>> > b/drivers/gpu/drm/i915/display/intel_bios.h
>> > index e375405a7828..da01b13260ae 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_bios.h
>> > +++ b/drivers/gpu/drm/i915/display/intel_bios.h
>> > @@ -231,6 +231,13 @@ struct mipi_pps_data {
>> >     u16 panel_power_cycle_delay;
>> >  } __packed;
>> >
>> > +enum panel_type {
>> > +   PANEL_TYPE_OPREGION,
>> > +   PANEL_TYPE_VBT,
>> > +   PANEL_TYPE_PNPID,
>> > +   PANEL_TYPE_FALLBACK,
>> > +};
>> > +

I don't want enum panel_type exposed from intel_bios.c at all, there's
no reason for that.

>> >  void intel_bios_init(struct drm_i915_private *dev_priv);  void
>> > intel_bios_init_panel(struct drm_i915_private *dev_priv,
>> >                        struct intel_panel *panel,
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>> > b/drivers/gpu/drm/i915/display/intel_dp.c
>> > index c19e99ee06b6..6f7afa75ec4d 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> > @@ -5222,6 +5222,9 @@ static bool intel_edp_init_connector(struct intel_dp
>> *intel_dp,
>> >             return false;
>> >     }
>> >
>> > +   intel_bios_init_panel(dev_priv, &intel_connector->panel,
>> > +                         encoder->devdata, NULL);
>>
>> We don't want to go for the fallback type here if we the VBT wants us to use
>> pnpid. Maybe we should just remove the fallback type entirely? Or perhaps only
>> use it if the VBT panel type is entirely invalid?
>
> Ok, Can I add like below?
> If (!PANEL_TYPE_FALLBACK)
>         intel_pps_init(intel_dp);
>
> But to read EDID pps_init should be called before it. Or else I can enable both the pps and later disable the unused one.

The first call should init everything if it can (panel type is *not*
pnpid). Fallback is fine in that case too.

If panel type indicates pnpid, intel_bios_init_panel() should set the
pps id to, say, -1, so intel_pps_init() or more specifically
bxt_power_sequencer_idx() can use some default or look at the hardware
or whatever.

intel_bios_init_panel() should probably also return a value on pnpid
indicating intel_edp_init_connector() should call
intel_bios_init_panel() again, this time with EDID. (Note: I kind of
like separating returning the value and setting the pps id to -1. I
don't want intel_edp_init_connector() to look at pps id, that's for pps,
and I don't want to pass flags all the way to bxt_power_sequencer_idx()
either.)


BR,
Jani.


>
> Regards,
> Animesh
>
>> > +
>> >     intel_pps_init(intel_dp);
>> >
>> >     /* Cache DPCD and EDID for edp. */
>> > @@ -5255,9 +5258,9 @@ static bool intel_edp_init_connector(struct intel_dp
>> *intel_dp,
>> >             edid = ERR_PTR(-ENOENT);
>> >     }
>> >     intel_connector->edid = edid;
>> > -
>> > -   intel_bios_init_panel(dev_priv, &intel_connector->panel,
>> > -                         encoder->devdata, IS_ERR(edid) ? NULL : edid);
>> > +   if (intel_connector->panel.vbt.panel_type == PANEL_TYPE_FALLBACK)
>> > +           intel_bios_init_panel(dev_priv, &intel_connector->panel,
>> > +                                 encoder->devdata, IS_ERR(edid) ? NULL :
>> edid);
>> >
>> >     intel_panel_add_edid_fixed_modes(intel_connector,
>> >                                      intel_connector->panel.vbt.drrs_type
>> != DRRS_TYPE_NONE, diff
>> > --git a/drivers/gpu/drm/i915/display/intel_pps.c
>> > b/drivers/gpu/drm/i915/display/intel_pps.c
>> > index b972fa6ec00d..4b8413382c5d 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_pps.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_pps.c
>> > @@ -1430,7 +1430,7 @@ void intel_pps_init(struct intel_dp *intel_dp)
>> >     intel_dp->pps.initializing = true;
>> >     INIT_DELAYED_WORK(&intel_dp->pps.panel_vdd_work,
>> > edp_panel_vdd_work);
>> >
>> > -   if (IS_GEMINILAKE(i915) || IS_BROXTON(i915))
>> > +   if (IS_GEMINILAKE(i915) || IS_BROXTON(i915) || DISPLAY_VER(i915) >=
>> > +12)
>> >             intel_dp->get_pps_idx = bxt_power_sequencer_idx;
>> >     else if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
>> >             intel_dp->get_pps_idx = vlv_power_sequencer_pipe;
>> > --
>> > 2.29.0
>>
>> --
>> Ville Syrjälä
>> Intel

-- 
Jani Nikula, Intel Open Source Graphics Center