Re: [RFC 2/3] drm/i915/alpm: Add compute config for lobf

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

On Mon, 04 Mar 2024, Animesh Manna <animesh.manna@intel.com> wrote:
> Link Off Between Active Frames, is a new feature for eDP
> that allows the panel to go to lower power state after
> transmission of data. This is a feature on top of ALPM, AS SDP.
> Add compute config during atomic-check phase.
>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  .../drm/i915/display/intel_display_types.h    |  3 ++
>  drivers/gpu/drm/i915/display/intel_dp.c       |  1 +
>  drivers/gpu/drm/i915/display/intel_psr.c      | 45 +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_psr.h      |  3 ++
>  4 files changed, 52 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index d473d8dca90a..4d2161eeb686 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1851,6 +1851,9 @@ struct intel_dp {
>  		u8 silence_period_sym_clocks;
>  		u8 lfps_half_cycle_num_of_syms;
>  	} alpm_parameters;
> +
> +	/* LOBF flags*/
> +	bool lobf_supported;
>  };
>  
>  enum lspcon_vendor {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 8304ef912767..e34b70d88b9a 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2979,6 +2979,7 @@ 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, conn_state);
>  	intel_psr_compute_config(intel_dp, pipe_config, conn_state);
> +	intel_psr_lobf_compute_config(intel_dp, pipe_config, conn_state);
>  	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);
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 4adcddba69c1..c08bffc2921a 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -436,6 +436,16 @@ static bool intel_dp_get_alpm_status(struct intel_dp *intel_dp)
>  	return alpm_caps & DP_ALPM_CAP;
>  }
>  
> +static bool intel_dp_get_aux_less_alpm_status(struct intel_dp *intel_dp)
> +{
> +	u8 alpm_caps = 0;
> +
> +	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP,
> +			      &alpm_caps) != 1)

The compute config path must not access the hardware.

BR,
Jani.

> +		return false;
> +	return alpm_caps & DP_ALPM_AUX_LESS_CAP;
> +}
> +
>  static u8 intel_dp_get_sink_sync_latency(struct intel_dp *intel_dp)
>  {
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> @@ -1569,6 +1579,41 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>  	crtc_state->has_psr2 = intel_psr2_config_valid(intel_dp, crtc_state);
>  }
>  
> +void intel_psr_lobf_compute_config(struct intel_dp *intel_dp,
> +			       struct intel_crtc_state *crtc_state,
> +			       struct drm_connector_state *conn_state)
> +{
> +	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +	int waketime_in_lines, first_sdp_position;
> +	int context_latency, guardband;
> +	bool auxless_alpm;
> +
> +	intel_dp->lobf_supported = false;
> +
> +	if (!intel_dp_is_edp(intel_dp))
> +		return;
> +
> +	if (!intel_dp_as_sdp_supported(intel_dp))
> +		return;
> +
> +	if (CAN_PSR(intel_dp) || CAN_PANEL_REPLAY(intel_dp))
> +		return;
> +
> +	if (_compute_alpm_params(intel_dp, crtc_state)) {
> +		context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
> +		guardband = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay - context_latency;
> +		first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start;
> +		auxless_alpm = intel_dp_get_aux_less_alpm_status(intel_dp);
> +		if (auxless_alpm)
> +			waketime_in_lines = intel_dp->alpm_parameters.io_wake_lines;
> +		else
> +			waketime_in_lines = intel_dp->alpm_parameters.aux_less_wake_lines;
> +
> +		if ((context_latency + guardband) > (first_sdp_position + waketime_in_lines))
> +			intel_dp->lobf_supported = true;
> +	}
> +}
> +
>  void intel_psr_get_config(struct intel_encoder *encoder,
>  			  struct intel_crtc_state *pipe_config)
>  {
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.h b/drivers/gpu/drm/i915/display/intel_psr.h
> index cde781df84d5..4bb77295288f 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.h
> +++ b/drivers/gpu/drm/i915/display/intel_psr.h
> @@ -40,6 +40,9 @@ void intel_psr_init(struct intel_dp *intel_dp);
>  void intel_psr_compute_config(struct intel_dp *intel_dp,
>  			      struct intel_crtc_state *crtc_state,
>  			      struct drm_connector_state *conn_state);
> +void intel_psr_lobf_compute_config(struct intel_dp *intel_dp,
> +				   struct intel_crtc_state *crtc_state,
> +				   struct drm_connector_state *conn_state);
>  void intel_psr_get_config(struct intel_encoder *encoder,
>  			  struct intel_crtc_state *pipe_config);
>  void intel_psr_irq_handler(struct intel_dp *intel_dp, u32 psr_iir);

-- 
Jani Nikula, Intel