[Intel-gfx] [PATCH 2/5] drm/i915: Parse EDID probed modes for DRRS support

[Jani Nikula]

On Tue, 17 Dec 2013, 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, based on the implementaion find_panel_downclock.
> 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.
>
> Signed-off-by: Pradeep Bhat <pradeep.bhat at intel.com>
> Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |    2 ++
>  drivers/gpu/drm/i915/intel_dp.c  |   47 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h |   29 +++++++++++++++++++++++
>  3 files changed, 78 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 02e11dc..c9bca16 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1462,8 +1462,10 @@ typedef struct drm_i915_private {
>  	/* Reclocking support */
>  	bool render_reclock_avail;
>  	bool lvds_downclock_avail;
> +	bool edp_downclock_avail;
>  	/* indicates the reduced downclock for LVDS*/
>  	int lvds_downclock;
> +	int edp_downclock;
>  	u16 orig_clock;
>  
>  	bool mchbar_need_disable;
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 82de200..935b46e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3524,6 +3524,48 @@ intel_dp_init_panel_power_sequencer_registers(struct drm_device *dev,
>  		      I915_READ(pp_div_reg));
>  }
>  
> +static void
> +intel_dp_drrs_initialize(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;
> +
> +	/**
> +	 * 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;
> +	}
> +
> +	/* First check if DRRS is enabled from VBT struct */
> +	if (!dev_priv->vbt.intel_drrs_enabled) {
> +		DRM_INFO("VBT doesn't support DRRS\n");
> +		return;
> +	}
> +
> +	intel_connector->panel.downclock_mode =	intel_find_panel_downclock(dev,
> +					fixed_mode, connector);
> +
> +	if (intel_connector->panel.downclock_mode != NULL &&
> +		dev_priv->vbt.drrs_mode == SEAMLESS_DRRS_SUPPORT) {
> +		dev_priv->edp_downclock_avail = true;
> +		dev_priv->edp_downclock =
> +			intel_connector->panel.downclock_mode->clock;
> +
> +		intel_dp->drrs_state.is_drrs_supported
> +				= dev_priv->vbt.drrs_mode;
> +
> +		intel_dp->drrs_state.drrs_refresh_rate_type = DRRS_HIGH_RR;
> +		DRM_INFO("SEAMLESS DRRS supported for eDP panel.\n");
> +	}
> +}
> +
>  static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  				     struct intel_connector *intel_connector)
>  {
> @@ -3537,6 +3579,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  	struct drm_display_mode *scan;
>  	struct edid *edid;
>  
> +	intel_dp->drrs_state.is_drrs_supported = DRRS_NOT_SUPPORTED;
> +
>  	if (!is_edp(intel_dp))
>  		return true;
>  
> @@ -3581,6 +3625,9 @@ 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 >= 5)
> +				intel_dp_drrs_initialize(intel_dig_port,
> +					intel_connector, fixed_mode);
>  			break;
>  		}
>  	}
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 9f8b465..6ec5f4e 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -462,6 +462,34 @@ struct intel_hdmi {
>  
>  #define DP_MAX_DOWNSTREAM_PORTS		0x10
>  
> +/**
> + * This enum is used to indicate the DRRS support type.
> + * The values of the enum map 1-to-1 with the values from VBT.
> + */
> +enum edp_panel_type {

This is about DRRS, not some fundamental "eDP panel type". The comment
above explains what this is, but why not make the enum self explanatory,
for example panel_drrs_support or something.

As to the 1-to-1 map mention, the vbt data is unsigned, but not
supported is -1 below...

> +	DRRS_NOT_SUPPORTED = -1,
> +	STATIC_DRRS_SUPPORT = 0,
> +	SEAMLESS_DRRS_SUPPORT = 2
> +};
> +/**
> + * 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 */
> +};
> +/**
> + * The drrs_info struct will represent the DRRS feature for eDP
> + * panel.
> + */
> +struct drrs_info {
> +	int is_drrs_supported;

IMHO anything that begins with "is" should be strictly boolean. When you
make this an enum per Chris' request, please change this as well. For
exampel drrs_support or something.

> +	int drrs_refresh_rate_type;
> +};
> +
>  struct intel_dp {
>  	uint32_t output_reg;
>  	uint32_t aux_ch_ctl_reg;
> @@ -487,6 +515,7 @@ struct intel_dp {
>  	bool want_panel_vdd;
>  	bool psr_setup_done;
>  	struct intel_connector *attached_connector;
> +	struct drrs_info drrs_state;
>  };
>  
>  struct intel_digital_port {
> -- 
> 1.7.9.5
>
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-- 
Jani Nikula, Intel Open Source Technology Center