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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

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.


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...

> 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@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