[PATCH v10 2/4] drm/i915/lobf: Move Lobf compute config after vblank adjustement

[Manna, Animesh]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Thursday, September 12, 2024 5:40 AM
> To: Manna, Animesh <animesh.manna at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Nikula, Jani <jani.nikula at intel.com>;
> Hogander, Jouni <jouni.hogander at intel.com>; Murthy, Arun R
> <arun.r.murthy at intel.com>; Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>;
> Golani, Mitulkumar Ajitkumar <mitulkumar.ajitkumar.golani at intel.com>
> Subject: Re: [PATCH v10 2/4] drm/i915/lobf: Move Lobf compute config after
> vblank adjustement
> 
> On Thu, Sep 05, 2024 at 10:48:39AM +0530, Animesh Manna wrote:
> > As lobf compute config is depends upon delayed vbalnk so moved
> 
> Actually no.
> 
> The code is as follows:
>  guardband = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay -
> context_latency;
> 
> Add context_latency to both sides:
>  context_latency + guardband = adjusted_mode->crtc_vtotal -
> adjusted_mode->crtc_vdisplay;
> 
> Substitute into:
>  crtc_state->has_lobf = (context_latency + guardband) >
> 	                (first_sdp_position + waketime_in_lines);
> 
> and you have no vblank delay anywhere.

Got your point, maybe will drop this patch as context_latency + guardband will be same even if we change the vblank_start.

> 
> 
> Someone should just rewrite that to use that simple formula.
> 
> Now, that code is using the non-VRR timings for all this computation so
> technically it might not even be computing the correct thing when using VRR,
> but I guess that's more of a problem for the "let's use the VRR timing
> generator fixed refersh stuff" because we really should match the non-VRR
> timings there...

Yeah, LOBF is only applicable for VRR timing generator fixed refersh mode, will relook the above calculation once it is enabled.

Regards,
Animesh

> 
> > lobf compute config in encoder late config(). Lobf is only for edp
> > connector so introduced intel_dp_late_compute_config().
> >
> > v1: Initial version.
> > v2: Function name modified. [Jani]
> >
> > Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c | 5 +++++
> > drivers/gpu/drm/i915/display/intel_dp.c  | 9 ++++++++-
> > drivers/gpu/drm/i915/display/intel_dp.h  | 2 ++
> >  3 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index 00fbe9f8c03a..0d12c94793bf 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -4367,6 +4367,11 @@ static int intel_ddi_compute_config_late(struct
> intel_encoder *encoder,
> >  			port_sync_transcoders & ~BIT(crtc_state-
> >cpu_transcoder);
> >  	}
> >
> > +	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP) ||
> > +	    intel_crtc_has_type(crtc_state, INTEL_OUTPUT_EDP)) {
> > +		intel_dp_compute_config_late(encoder, crtc_state);
> > +	}
> > +
> >  	return 0;
> >  }
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 86bc6d79279f..bc0042a1bc3a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -3107,7 +3107,6 @@ intel_dp_compute_config(struct intel_encoder
> *encoder,
> >  	intel_vrr_compute_config(pipe_config, conn_state);
> >  	intel_dp_compute_as_sdp(intel_dp, pipe_config);
> >  	intel_psr_compute_config(intel_dp, pipe_config, conn_state);
> > -	intel_alpm_lobf_compute_config(intel_dp, pipe_config);
> >  	intel_dp_drrs_compute_config(connector, pipe_config,
> link_bpp_x16);
> >  	intel_dp_compute_vsc_sdp(intel_dp, pipe_config, conn_state);
> >  	intel_dp_compute_hdr_metadata_infoframe_sdp(intel_dp,
> pipe_config,
> > conn_state); @@ -3116,6 +3115,14 @@ intel_dp_compute_config(struct
> intel_encoder *encoder,
> >  							pipe_config);
> >  }
> >
> > +void intel_dp_compute_config_late(struct intel_encoder *encoder,
> > +				  struct intel_crtc_state *crtc_state) {
> > +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > +
> > +	intel_alpm_lobf_compute_config(intel_dp, crtc_state); }
> > +
> >  void intel_dp_set_link_params(struct intel_dp *intel_dp,
> >  			      int link_rate, int lane_count)  { diff --git
> > a/drivers/gpu/drm/i915/display/intel_dp.h
> > b/drivers/gpu/drm/i915/display/intel_dp.h
> > index 1b9aaddd8c35..411feece9acb 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.h
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> > @@ -74,6 +74,8 @@ void intel_dp_encoder_flush_work(struct
> drm_encoder
> > *encoder);  int intel_dp_compute_config(struct intel_encoder *encoder,
> >  			    struct intel_crtc_state *pipe_config,
> >  			    struct drm_connector_state *conn_state);
> > +void intel_dp_compute_config_late(struct intel_encoder *encoder,
> > +				  struct intel_crtc_state *crtc_state);
> >  int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  				struct intel_crtc_state *pipe_config,
> >  				struct drm_connector_state *conn_state,
> > --
> > 2.29.0
> 
> --
> Ville Syrjälä
> Intel