[PATCH v4 4/5] drm/i915/psr: Enable ALPM for eDP Panel replay

[Manna, Animesh]

> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander at intel.com>
> Sent: Friday, March 15, 2024 1:32 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>; Manna, Animesh
> <animesh.manna at intel.com>; Murthy, Arun R <arun.r.murthy at intel.com>;
> Hogander, Jouni <jouni.hogander at intel.com>
> Subject: [PATCH v4 4/5] drm/i915/psr: Enable ALPM for eDP Panel replay
> 
> Enable ALPM AUX-Less for Panel Replay eDP. Also write all calculated AUX-
> Less configuration values accordingly.
> 
> Bspec: 71477
> 
> v4:
>   - add comment explaining why AUX less is enabled on eDP panel replay
>     without any extra checks
> v3:
>   - do not use alpm_ctl as uninitialized variable
> v2:
>   - do not set AUX-Wake related bits for AUX-Less case
>   - drop switch to active latency
>   - add SLEEP_HOLD_TIME_50_SYMBOLS
>   - add PORT_ALPM_CTL_MAX_PHY_SWING_HOLD
> 
> Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 47 ++++++++++++++++++++++--
>  1 file changed, 43 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> b/drivers/gpu/drm/i915/display/intel_psr.c
> index 9429c5002986..05b30dc63b3d 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -1721,14 +1721,43 @@ static void lnl_alpm_configure(struct intel_dp
> *intel_dp)
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>  	enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
>  	struct intel_psr *psr = &intel_dp->psr;
> +	u32 alpm_ctl;
> 
>  	if (DISPLAY_VER(dev_priv) < 20)
>  		return;
> 
> -	intel_de_write(dev_priv, ALPM_CTL(cpu_transcoder),
> -		       ALPM_CTL_EXTENDED_FAST_WAKE_ENABLE |
> -		       ALPM_CTL_ALPM_ENTRY_CHECK(psr-
> >alpm_parameters.check_entry_lines) |
> -		       ALPM_CTL_EXTENDED_FAST_WAKE_TIME(psr-
> >alpm_parameters.fast_wake_lines));
> +	/*
> +	 * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
> +	 * check panel support at this point.
> +	 */
> +	if (intel_dp->psr.panel_replay_enabled &&
> intel_dp_is_edp(intel_dp)) {
> +		alpm_ctl = ALPM_CTL_ALPM_ENABLE |
> +			ALPM_CTL_ALPM_AUX_LESS_ENABLE |
> +
> 	ALPM_CTL_AUX_LESS_SLEEP_HOLD_TIME_50_SYMBOLS;
> +
> +		intel_de_write(dev_priv, PORT_ALPM_CTL(cpu_transcoder),
> +			       PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE |
> +			       PORT_ALPM_CTL_MAX_PHY_SWING_SETUP(15) |
> +			       PORT_ALPM_CTL_MAX_PHY_SWING_HOLD(0) |
> +			       PORT_ALPM_CTL_SILENCE_PERIOD(
> +				       psr-
> >alpm_parameters.silence_period_sym_clocks));
> +
> +		intel_de_write(dev_priv,
> PORT_ALPM_LFPS_CTL(cpu_transcoder),
> +			       PORT_ALPM_LFPS_CTL_LFPS_CYCLE_COUNT(10) |
> +
> PORT_ALPM_LFPS_CTL_LFPS_HALF_CYCLE_DURATION(
> +				       psr-
> >alpm_parameters.lfps_half_cycle_num_of_syms) |
> +
> PORT_ALPM_LFPS_CTL_FIRST_LFPS_HALF_CYCLE_DURATION(
> +				       psr-
> >alpm_parameters.lfps_half_cycle_num_of_syms) |
> +
> PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION(
> +				       psr-
> >alpm_parameters.lfps_half_cycle_num_of_syms));
> +	} else {
> +		alpm_ctl = ALPM_CTL_EXTENDED_FAST_WAKE_ENABLE |
> +			ALPM_CTL_EXTENDED_FAST_WAKE_TIME(psr-
> >alpm_parameters.fast_wake_lines);
> +	}
> +
> +	alpm_ctl |=
> +ALPM_CTL_ALPM_ENTRY_CHECK(psr-
> >alpm_parameters.check_entry_lines);
> +
> +	intel_de_write(dev_priv, ALPM_CTL(cpu_transcoder), alpm_ctl);
>  }
> 
>  static void intel_psr_enable_source(struct intel_dp *intel_dp, @@ -1999,6
> +2028,16 @@ static void intel_psr_disable_locked(struct intel_dp *intel_dp)
> 
>  	intel_snps_phy_update_psr_power_state(dev_priv, phy, false);
> 
> +	/* Panel Replay on eDP is always using ALPM aux less. */
> +	if (intel_dp->psr.panel_replay_enabled &&
> intel_dp_is_edp(intel_dp)) {
> +		intel_de_rmw(dev_priv, ALPM_CTL(cpu_transcoder),
> +			     ALPM_CTL_ALPM_ENABLE |
> +			     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> +
> +		intel_de_rmw(dev_priv, PORT_ALPM_CTL(cpu_transcoder),
> +			     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> +	}

This patch only enable source for aux-less alpm. Good to modify the commit title mentioning the same or else a 'TODO:' comment can be added if sink support enabling is planned in a separate patch.

Regards,
Animesh
> +
>  	/* Disable PSR on Sink */
>  	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, 0);
> 
> --
> 2.34.1