[Intel-gfx] [PATCH 2/6] drm/i915: Parse EDID probed modes for DRRS support

[Jani Nikula]

This and the following patches need to be rebased on top of current
-nightly.

On Fri, 07 Mar 2014, Vandana Kannan <vandana.kannan at intel.com> wrote:
> From: Pradeep Bhat <pradeep.bhat at intel.com>
>
> This patch and finds out the lowest refresh rate supported for the resolution
> same as the fixed_mode.
> It also checks the VBT fields to see if panel supports seamless DRRS or not.
> Based on above data it marks whether eDP panel supports seamless DRRS or not.
> This information is needed for supporting seamless DRRS switch for certain
> power saving usecases. This patch is tested by enabling the DRM logs and
> user should see whether Seamless DRRS is supported or not.
>
> v2: Daniel's review comments
> Modified downclock deduction based on intel_find_panel_downclock
>
> v3: Chris's review comments
> Moved edp_downclock_avail and edp_downclock to intel_panel
>
> v4: Jani's review comments.
> Changed name of the enum edp_panel_type to drrs_support type.
> Change is_drrs_supported to drrs_support of type enum drrs_support_type.
>
> v5: Incorporated Jani's review comments
> Modify intel_dp_drrs_initialize to return downclock mode. Support for Gen7
> and above.
>
> v6: Incorporated Chris's review comments.
> Changed initialize to init in intel_drrs_initialize
>
> Signed-off-by: Pradeep Bhat <pradeep.bhat at intel.com>
> Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c  |   54 +++++++++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h |   20 ++++++++++++++
>  2 files changed, 73 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 88cc9d3..39365bf 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3666,6 +3666,50 @@ intel_dp_init_panel_power_sequencer_registers(struct drm_device *dev,
>  		      I915_READ(pp_div_reg));
>  }
>  
> +static struct drm_display_mode *
> +intel_dp_drrs_init(struct intel_digital_port *intel_dig_port,
> +			struct intel_connector *intel_connector,
> +			struct drm_display_mode *fixed_mode)
> +{
> +	struct drm_connector *connector = &intel_connector->base;
> +	struct intel_dp *intel_dp = &intel_dig_port->dp;
> +	struct drm_device *dev = intel_dig_port->base.base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_display_mode *downclock_mode = NULL;
> +
> +	/**
> +	 * Check if PSR is supported by panel and enabled
> +	 * if so then DRRS is reported as not supported for Haswell.
> +	 */
> +	if (INTEL_INFO(dev)->gen < 8 &&	intel_edp_is_psr_enabled(dev)) {
> +		DRM_INFO("eDP panel has PSR enabled. Cannot support DRRS\n");
> +		return downclock_mode;

Just return NULL explicitly if that's the intention.

> +	}
> +
> +	/* First check if DRRS is enabled from VBT struct */
> +	if (dev_priv->vbt.drrs_type == DRRS_NOT_SUPPORTED) {
> +		DRM_INFO("VBT doesn't support DRRS\n");
> +		return downclock_mode;

Same here.

> +	}
> +
> +	downclock_mode = intel_find_panel_downclock
> +					(dev, fixed_mode, connector);
> +
> +	if (downclock_mode != NULL &&
> +		dev_priv->vbt.drrs_type == SEAMLESS_DRRS_SUPPORT) {
> +		intel_connector->panel.edp_downclock_avail = true;
> +		intel_connector->panel.edp_downclock =
> +			downclock_mode->clock;

Why do you need a copy of downclock_mode->clock in
intel_connector->panel.edp_downclock? You can always get that through
intel_connector->panel.downclock_mode->clock. Single point of truth.

> +
> +		intel_dp->drrs_state.type = dev_priv->vbt.drrs_type;
> +
> +		intel_dp->drrs_state.refresh_rate_type = DRRS_HIGH_RR;
> +		DRM_INFO("seamless DRRS supported for eDP panel.\n");
> +	}
> +
> +	return downclock_mode;
> +}
> +
>  static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  				     struct intel_connector *intel_connector,
>  				     struct edp_power_seq *power_seq)
> @@ -3675,10 +3719,13 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  	struct drm_device *dev = intel_dig_port->base.base.dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_display_mode *fixed_mode = NULL;
> +	struct drm_display_mode *downclock_mode = NULL;
>  	bool has_dpcd;
>  	struct drm_display_mode *scan;
>  	struct edid *edid;
>  
> +	intel_dp->drrs_state.type = DRRS_NOT_SUPPORTED;
> +
>  	if (!is_edp(intel_dp))
>  		return true;
>  
> @@ -3720,6 +3767,11 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  	list_for_each_entry(scan, &connector->probed_modes, head) {
>  		if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
>  			fixed_mode = drm_mode_duplicate(dev, scan);
> +			if (INTEL_INFO(dev)->gen > 6)

It seems to me this condition should be inside intel_dp_drrs_init().

> +				downclock_mode =
> +					intel_dp_drrs_init(
> +						intel_dig_port,
> +						intel_connector, fixed_mode);
>  			break;
>  		}
>  	}
> @@ -3732,7 +3784,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  			fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
>  	}
>  
> -	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
> +	intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
>  	intel_panel_setup_backlight(connector);
>  
>  	return true;
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 6aa549a..c41c735 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -168,6 +168,9 @@ struct intel_panel {
>  		bool active_low_pwm;
>  		struct backlight_device *device;
>  	} backlight;
> +
> +	bool edp_downclock_avail;
> +	int edp_downclock;
>  };
>  
>  struct intel_connector {
> @@ -464,6 +467,22 @@ struct intel_hdmi {
>  
>  #define DP_MAX_DOWNSTREAM_PORTS		0x10
>  
> +/**
> + * HIGH_RR is the highest eDP panel refresh rate read from EDID
> + * LOW_RR is the lowest eDP panel refresh rate found from EDID
> + * parsing for same resolution.
> + */
> +enum edp_drrs_refresh_rate_type {
> +	DRRS_HIGH_RR,
> +	DRRS_LOW_RR,
> +	DRRS_MAX_RR, /* RR count */
> +};
> +
> +struct drrs_info {
> +	enum drrs_support_type type;
> +	enum edp_drrs_refresh_rate_type refresh_rate_type;
> +};
> +
>  struct intel_dp {
>  	uint32_t output_reg;
>  	uint32_t aux_ch_ctl_reg;
> @@ -503,6 +522,7 @@ struct intel_dp {
>  				     bool has_aux_irq,
>  				     int send_bytes,
>  				     uint32_t aux_clock_divider);
> +	struct drrs_info drrs_state;

Any reason this isn't an unnamed struct here? And if you need the name,
why is it different from the field name? drrs_info vs. drrs_state.

>  };
>  
>  struct intel_digital_port {
> -- 
> 1.7.9.5
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center