Re: [PATCH v4 2/8] drm/i915/lobf: Disintegrate alpm_disable from psr_disable

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

On Mon, 24 Feb 2025, Animesh Manna <animesh.manna@intel.com> wrote:
> Currently clearing of alpm registers is done through psr_disable()
> which is always not correct, without psr also alpm can exist. So
> dis-integrate alpm_disable() from psr_disable().
>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_alpm.c     | 21 +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_alpm.h     |  1 +
>  drivers/gpu/drm/i915/display/intel_ddi.c      |  2 ++
>  .../drm/i915/display/intel_display_types.h    |  1 +
>  drivers/gpu/drm/i915/display/intel_psr.c      | 11 ----------
>  5 files changed, 25 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
> index a53ed83f6b22..d94c96ba46b1 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> @@ -365,6 +365,7 @@ void intel_alpm_configure(struct intel_dp *intel_dp,
>  			  const struct intel_crtc_state *crtc_state)
>  {
>  	lnl_alpm_configure(intel_dp, crtc_state);
> +	intel_dp->alpm_parameters.transcoder = crtc_state->cpu_transcoder;

Why do we need to store this?

>  }
>  
>  void intel_alpm_post_plane_update(struct intel_atomic_state *state,
> @@ -440,3 +441,23 @@ void intel_alpm_lobf_debugfs_add(struct intel_connector *connector)
>  	debugfs_create_file("i915_edp_lobf_info", 0444, root,
>  			    connector, &i915_edp_lobf_info_fops);
>  }
> +
> +void intel_alpm_disable(struct intel_dp *intel_dp)
> +{
> +	struct intel_display *display = to_intel_display(intel_dp);
> +	enum transcoder cpu_transcoder = intel_dp->alpm_parameters.transcoder;
> +
> +	if (DISPLAY_VER(display) < 20)
> +		return;
> +
> +	if (!(intel_de_read(display, ALPM_CTL(display, cpu_transcoder)) & ALPM_CTL_ALPM_ENABLE))
> +		return;

Why are we checking the hardware state here? We should know what state
the hardware is in, right?

> +
> +	intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
> +		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
> +		     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> +
> +	intel_de_rmw(display,
> +		     PORT_ALPM_CTL(cpu_transcoder),
> +		     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h b/drivers/gpu/drm/i915/display/intel_alpm.h
> index 2f862b0476a8..91f51fb24f98 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> @@ -28,4 +28,5 @@ void intel_alpm_post_plane_update(struct intel_atomic_state *state,
>  void intel_alpm_lobf_debugfs_add(struct intel_connector *connector);
>  bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp);
>  bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp);
> +void intel_alpm_disable(struct intel_dp *intel_dp);
>  #endif
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 7937f4de66cb..26aa32d4d50e 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -35,6 +35,7 @@
>  #include "i915_drv.h"
>  #include "i915_reg.h"
>  #include "icl_dsi.h"
> +#include "intel_alpm.h"
>  #include "intel_audio.h"
>  #include "intel_audio_regs.h"
>  #include "intel_backlight.h"
> @@ -3570,6 +3571,7 @@ static void intel_ddi_disable_dp(struct intel_atomic_state *state,
>  	intel_dp->link_trained = false;
>  
>  	intel_psr_disable(intel_dp, old_crtc_state);
> +	intel_alpm_disable(intel_dp);

We have old crtc state here, why do we save the transcoder to intel_dp
and use that?

>  	intel_edp_backlight_off(old_conn_state);
>  	/* Disable the decompression in DP Sink */
>  	intel_dp_sink_disable_decompression(state,
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 4440521e3e9e..b78721c451b8 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1801,6 +1801,7 @@ struct intel_dp {
>  	struct {
>  		u8 io_wake_lines;
>  		u8 fast_wake_lines;
> +		enum transcoder transcoder;
>  
>  		/* LNL and beyond */
>  		u8 check_entry_lines;
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index c1dd9c739fd4..1d202f2eb356 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -2141,17 +2141,6 @@ static void intel_psr_disable_locked(struct intel_dp *intel_dp)
>  	if (intel_dp_is_edp(intel_dp))
>  		intel_snps_phy_update_psr_power_state(&dp_to_dig_port(intel_dp)->base, 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(display, ALPM_CTL(display, cpu_transcoder),
> -			     ALPM_CTL_ALPM_ENABLE |
> -			     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> -
> -		intel_de_rmw(display,
> -			     PORT_ALPM_CTL(cpu_transcoder),
> -			     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> -	}
> -
>  	/* Disable PSR on Sink */
>  	if (!intel_dp->psr.panel_replay_enabled) {
>  		drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, 0);

-- 
Jani Nikula, Intel