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

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Fri, 2024-05-03 at 08:19 +0000, Manna, Animesh wrote:
> 
> 
> > -----Original Message-----
> > From: Hogander, Jouni <jouni.hogander@intel.com>
> > Sent: Friday, May 3, 2024 1:18 PM
> > To: Manna, Animesh <animesh.manna@intel.com>; intel-
> > gfx@lists.freedesktop.org
> > Cc: dri-devel@lists.freedesktop.org; Murthy, Arun R
> > <arun.r.murthy@intel.com>; Nikula, Jani <jani.nikula@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@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?

No, I was just wondering why this is missing from your patch set?

BR,

Jouni Högander

> 
> 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
>