[PATCH v3 5/6] drm/i915/alpm: Enable lobf from source in ALPM_CTL

[Manna, Animesh]

> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander at intel.com>
> Sent: Friday, May 3, 2024 1:18 PM
> To: Manna, Animesh <animesh.manna at intel.com>; intel-
> gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Murthy, Arun R
> <arun.r.murthy at intel.com>; Nikula, Jani <jani.nikula at intel.com>
> Subject: Re: [PATCH v3 5/6] drm/i915/alpm: Enable lobf from source in
> ALPM_CTL
> 
> On Thu, 2024-04-25 at 00:08 +0530, Animesh Manna wrote:
> > Set the Link Off Between Frames Enable bit in ALPM_CTL register.
> >
> > Note: Lobf need to be enabled adaptive sync fixed refresh mode where
> > vmin = vmax = flipline, which will arise after cmmr feature
> > enablement. Will add enabling sequence in a separate patch.
> 
> Is adaptive sync needed for both Aux Wake and Aux Less Wake?
 
AFAIK, ALPM (aux-wake/aux-less) do not have any dependency on adaptive sync.
But LOBF is dependent on ALPM (aux-wake/aux-less) and adaptive sync fixed refresh mode.

> 
> >
> > Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_alpm.c | 13 +++++++++----
> >  drivers/gpu/drm/i915/display/intel_alpm.h |  4 ++--
> >  drivers/gpu/drm/i915/display/intel_psr.c  |  2 +-
> >  3 files changed, 12 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> > b/drivers/gpu/drm/i915/display/intel_alpm.c
> > index 3bb69ed16aab..b08799586b58 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> > @@ -290,10 +290,11 @@ void intel_alpm_compute_lobf_config(struct
> > intel_dp *intel_dp,
> >         }
> >  }
> >
> > -static void lnl_alpm_configure(struct intel_dp *intel_dp)
> > +static void lnl_alpm_configure(struct intel_dp *intel_dp,
> > +                              const struct intel_crtc_state
> > *crtc_state)
> >  {
> >         struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > -       enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
> > +       enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> >         u32 alpm_ctl;
> >
> >         if (DISPLAY_VER(dev_priv) < 20 || (!intel_dp-
> > >psr.psr2_enabled &&
> > @@ -329,12 +330,16 @@ static void lnl_alpm_configure(struct intel_dp
> > *intel_dp)
> >                            ALPM_CTL_EXTENDED_FAST_WAKE_TIME(intel_dp-
> > >alpm_parameters.fast_wake_lines);
> >         }
> >
> > +       if (crtc_state->has_lobf)
> > +               alpm_ctl |= ALPM_CTL_LOBF_ENABLE;
> > +
> 
> How you are planning to differentiate between AUX Wake and AUX Less
> Wake for LOBF?

LOBF can be enabled in both aux-wake or aux-less alpm. So, check for aux-wake or aux-less is not needed.
For aux wake ALPM_CTL[ ALPM AUX Less Enable ] = 0
and for aux less ALPM_CTL[ ALPM AUX Less Enable ] = 1.
So, I am plaining to add has_lobf check and enable if needed before ALPM_CTL register is getting programmed. Do you see any issue here?

Regards,
Animesh

> 
> BR,
> 
> Jouni Högander
> 
> >         alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp-
> > >alpm_parameters.check_entry_lines);
> >
> >         intel_de_write(dev_priv, ALPM_CTL(cpu_transcoder), alpm_ctl);
> >  }
> >
> > -void intel_alpm_configure(struct intel_dp *intel_dp)
> > +void intel_alpm_configure(struct intel_dp *intel_dp,
> > +                         const struct intel_crtc_state *crtc_state)
> >  {
> > -       lnl_alpm_configure(intel_dp);
> > +       lnl_alpm_configure(intel_dp, crtc_state);
> >  }
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h
> > b/drivers/gpu/drm/i915/display/intel_alpm.h
> > index b9602b71d28f..a9ca190da3e4 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> > @@ -18,6 +18,6 @@ bool intel_alpm_compute_params(struct intel_dp
> > *intel_dp,
> >  void intel_alpm_compute_lobf_config(struct intel_dp *intel_dp,
> >                                     struct intel_crtc_state
> > *crtc_state,
> >                                     struct drm_connector_state
> > *conn_state); -void intel_alpm_configure(struct intel_dp *intel_dp);
> > -
> > +void intel_alpm_configure(struct intel_dp *intel_dp,
> > +                         const struct intel_crtc_state *crtc_state);
> >  #endif
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index c4ab289dbc15..4eb45df20ad2 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1611,7 +1611,7 @@ static void intel_psr_enable_source(struct
> > intel_dp *intel_dp,
> >                              IGNORE_PSR2_HW_TRACKING : 0);
> >
> >         if (intel_dp_is_edp(intel_dp))
> > -               intel_alpm_configure(intel_dp);
> > +               intel_alpm_configure(intel_dp, crtc_state);
> >
> >         /*
> >          * Wa_16013835468