Re: [Intel-gfx] [PATCH v3 16/16] drm/i915: Convert fixed_mode/downclock_mode into a list

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

On Fri, 11 Mar 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Store the fixed_mode and downclock_mode as a real list,
> in preparation for exposing other supported modes as well.
>
> v2: Init the list in intel_sdvo_connector_alloc() too
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Even for the two mode case this makes stuff cleaner!

One nitpick below, regardless,

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  .../gpu/drm/i915/display/intel_connector.c    |  2 +
>  .../drm/i915/display/intel_display_debugfs.c  |  9 +-
>  .../drm/i915/display/intel_display_types.h    |  3 +-
>  drivers/gpu/drm/i915/display/intel_panel.c    | 82 ++++++++++---------
>  drivers/gpu/drm/i915/display/intel_sdvo.c     |  2 +
>  5 files changed, 53 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
> index c65f95a9a1ec..a5f5dd55b0cb 100644
> --- a/drivers/gpu/drm/i915/display/intel_connector.c
> +++ b/drivers/gpu/drm/i915/display/intel_connector.c
> @@ -54,6 +54,8 @@ int intel_connector_init(struct intel_connector *connector)
>  	__drm_atomic_helper_connector_reset(&connector->base,
>  					    &conn_state->base);
>  
> +	INIT_LIST_HEAD(&connector->panel.fixed_modes);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 35c27d67d584..b3d426cc3266 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -548,12 +548,15 @@ static void intel_encoder_info(struct seq_file *m,
>  static void intel_panel_info(struct seq_file *m,
>  			     struct intel_connector *connector)
>  {
> -	const struct drm_display_mode *fixed_mode = connector->panel.fixed_mode;
> +	const struct drm_display_mode *fixed_mode;
>  
> -	if (!fixed_mode)
> +	if (list_empty(&connector->panel.fixed_modes))
>  		return;
>  
> -	seq_printf(m, "\tfixed mode: " DRM_MODE_FMT "\n", DRM_MODE_ARG(fixed_mode));
> +	seq_puts(m, "\tfixed modes:\n");
> +
> +	list_for_each_entry(fixed_mode, &connector->panel.fixed_modes, head)
> +		intel_seq_print_mode(m, 2, fixed_mode);
>  }
>  
>  static void intel_hdcp_info(struct seq_file *m,
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index e34800ab6924..d84e82f3eab9 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -280,8 +280,7 @@ struct intel_panel_bl_funcs {
>  };
>  
>  struct intel_panel {
> -	struct drm_display_mode *fixed_mode;
> -	struct drm_display_mode *downclock_mode;
> +	struct list_head fixed_modes;
>  
>  	/* backlight */
>  	struct {
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 08a0612edd60..2d5c09b1ab72 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -48,59 +48,59 @@ bool intel_panel_use_ssc(struct drm_i915_private *i915)
>  const struct drm_display_mode *
>  intel_panel_preferred_fixed_mode(struct intel_connector *connector)
>  {
> -	return connector->panel.fixed_mode;
> +	const struct drm_display_mode *fixed_mode;
> +
> +	list_for_each_entry(fixed_mode, &connector->panel.fixed_modes, head)
> +		return fixed_mode;
> +
> +	return NULL;

Nitpick, a bit verbose but self-documenting alternative:

	return list_first_entry_or_null(&connector->panel.fixed_modes, struct drm_display_mode, head);

>  }
>  
>  const struct drm_display_mode *
>  intel_panel_fixed_mode(struct intel_connector *connector,
>  		       const struct drm_display_mode *mode)
>  {
> -	const struct drm_display_mode *fixed_mode = connector->panel.fixed_mode;
> -	const struct drm_display_mode *downclock_mode = connector->panel.downclock_mode;
> +	const struct drm_display_mode *fixed_mode, *best_mode = NULL;
> +	int vrefresh = drm_mode_vrefresh(mode);
>  
> -	/* pick the one that is closer in terms of vrefresh */
> -	/* FIXME make this a a list of modes so we can have more than two */
> -	if (fixed_mode && downclock_mode &&
> -	    abs(drm_mode_vrefresh(downclock_mode) - drm_mode_vrefresh(mode)) <
> -	    abs(drm_mode_vrefresh(fixed_mode) - drm_mode_vrefresh(mode)))
> -		return downclock_mode;
> -	else
> -		return fixed_mode;
> +	/* pick the fixed_mode that is closest in terms of vrefresh */
> +	list_for_each_entry(fixed_mode, &connector->panel.fixed_modes, head) {
> +		if (!best_mode ||
> +		    abs(drm_mode_vrefresh(fixed_mode) - vrefresh) <
> +		    abs(drm_mode_vrefresh(best_mode) - vrefresh))
> +			best_mode = fixed_mode;
> +	}
> +
> +	return best_mode;
>  }
>  
>  const struct drm_display_mode *
>  intel_panel_downclock_mode(struct intel_connector *connector,
>  			   const struct drm_display_mode *adjusted_mode)
>  {
> -	const struct drm_display_mode *downclock_mode = connector->panel.downclock_mode;
> +	const struct drm_display_mode *fixed_mode, *best_mode = NULL;
> +	int vrefresh = drm_mode_vrefresh(adjusted_mode);
>  
> -	if (downclock_mode &&
> -	    drm_mode_vrefresh(downclock_mode) < drm_mode_vrefresh(adjusted_mode))
> -		return downclock_mode;
> -	else
> -		return NULL;
> +	/* pick the fixed_mode with the lowest refresh rate */
> +	list_for_each_entry(fixed_mode, &connector->panel.fixed_modes, head) {
> +		if (drm_mode_vrefresh(fixed_mode) < vrefresh) {
> +			vrefresh = drm_mode_vrefresh(fixed_mode);
> +			best_mode = fixed_mode;
> +		}
> +	}
> +
> +	return best_mode;
>  }
>  
>  int intel_panel_get_modes(struct intel_connector *connector)
>  {
> +	const struct drm_display_mode *fixed_mode;
>  	int num_modes = 0;
>  
> -	if (connector->panel.fixed_mode) {
> +	list_for_each_entry(fixed_mode, &connector->panel.fixed_modes, head) {
>  		struct drm_display_mode *mode;
>  
> -		mode = drm_mode_duplicate(connector->base.dev,
> -					  connector->panel.fixed_mode);
> -		if (mode) {
> -			drm_mode_probed_add(&connector->base, mode);
> -			num_modes++;
> -		}
> -	}
> -
> -	if (connector->panel.downclock_mode) {
> -		struct drm_display_mode *mode;
> -
> -		mode = drm_mode_duplicate(connector->base.dev,
> -					  connector->panel.downclock_mode);
> +		mode = drm_mode_duplicate(connector->base.dev, fixed_mode);
>  		if (mode) {
>  			drm_mode_probed_add(&connector->base, mode);
>  			num_modes++;
> @@ -114,7 +114,8 @@ enum drrs_type intel_panel_drrs_type(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *i915 = to_i915(connector->base.dev);
>  
> -	if (!connector->panel.downclock_mode)
> +	if (list_empty(&connector->panel.fixed_modes) ||
> +	    list_is_singular(&connector->panel.fixed_modes))
>  		return DRRS_TYPE_NONE;
>  
>  	return i915->vbt.drrs_type;
> @@ -608,8 +609,10 @@ int intel_panel_init(struct intel_panel *panel,
>  {
>  	intel_backlight_init_funcs(panel);
>  
> -	panel->fixed_mode = fixed_mode;
> -	panel->downclock_mode = downclock_mode;
> +	if (fixed_mode)
> +		list_add_tail(&fixed_mode->head, &panel->fixed_modes);
> +	if (downclock_mode)
> +		list_add_tail(&downclock_mode->head, &panel->fixed_modes);
>  
>  	return 0;
>  }
> @@ -618,13 +621,12 @@ void intel_panel_fini(struct intel_panel *panel)
>  {
>  	struct intel_connector *intel_connector =
>  		container_of(panel, struct intel_connector, panel);
> +	struct drm_display_mode *fixed_mode, *next;
>  
>  	intel_backlight_destroy(panel);
>  
> -	if (panel->fixed_mode)
> -		drm_mode_destroy(intel_connector->base.dev, panel->fixed_mode);
> -
> -	if (panel->downclock_mode)
> -		drm_mode_destroy(intel_connector->base.dev,
> -				panel->downclock_mode);
> +	list_for_each_entry_safe(fixed_mode, next, &panel->fixed_modes, head) {
> +		list_del(&fixed_mode->head);
> +		drm_mode_destroy(intel_connector->base.dev, fixed_mode);
> +	}
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
> index 6e0a4f48d84d..158e750e5b4d 100644
> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> @@ -2747,6 +2747,8 @@ static struct intel_sdvo_connector *intel_sdvo_connector_alloc(void)
>  	__drm_atomic_helper_connector_reset(&sdvo_connector->base.base,
>  					    &conn_state->base.base);
>  
> +	INIT_LIST_HEAD(&sdvo_connector->base.panel.fixed_modes);
> +
>  	return sdvo_connector;
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center