Re: [PATCH v8 12/12] drm/i915: Check TMDS clock DP to HDMI dongle

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Mika Kahola <mika.kahola@intel.com>
Cc: daniel.vetter@ffwll.ch, intel-gfx@lists.freedesktop.org,
	jim.bride@linux.intel.com, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v8 12/12] drm/i915: Check TMDS clock DP to HDMI dongle
Date: Thu, 8 Sep 2016 15:48:45 +0300	[thread overview]
Message-ID: <20160908124845.GY4329@intel.com> (raw)
In-Reply-To: <1471430989-28161-14-git-send-email-mika.kahola@intel.com>

On Wed, Aug 17, 2016 at 01:49:49PM +0300, Mika Kahola wrote:
> Respect max TMDS clock frequency from DPCD for active
> DP to HDMI adapters.
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_drv.h  |  3 +++
>  drivers/gpu/drm/i915/intel_hdmi.c | 27 +++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 1c700b0..b7fd551 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -817,6 +817,9 @@ struct intel_hdmi {
>  	i915_reg_t hdmi_reg;
>  	int ddc_bus;
>  	struct {
> +		int max_tmds_clock;
> +	} dp_to_hdmi;
> +	struct {
>  		enum drm_dp_dual_mode_type type;
>  		int max_tmds_clock;
>  	} dp_dual_mode;
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 4df9f38..1469d00 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1204,6 +1204,9 @@ static int hdmi_port_clock_limit(struct intel_hdmi *hdmi,
>  	int max_tmds_clock = intel_hdmi_source_max_tmds_clock(to_i915(dev));
>  
>  	if (respect_downstream_limits) {
> +		if (hdmi->dp_to_hdmi.max_tmds_clock)
> +			max_tmds_clock = min(max_tmds_clock,
> +					     hdmi->dp_to_hdmi.max_tmds_clock);
>  		if (hdmi->dp_dual_mode.max_tmds_clock)
>  			max_tmds_clock = min(max_tmds_clock,
>  					     hdmi->dp_dual_mode.max_tmds_clock);
> @@ -1373,11 +1376,33 @@ intel_hdmi_unset_edid(struct drm_connector *connector)
>  	intel_hdmi->dp_dual_mode.type = DRM_DP_DUAL_MODE_NONE;
>  	intel_hdmi->dp_dual_mode.max_tmds_clock = 0;
>  
> +	intel_hdmi->dp_to_hdmi.max_tmds_clock = 0;
> +
>  	kfree(to_intel_connector(connector)->detect_edid);
>  	to_intel_connector(connector)->detect_edid = NULL;
>  }
>  
>  static void
> +intel_hdmi_dp_adapter_detect(struct drm_connector *connector)
> +{
> +	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
> +	struct intel_digital_port *intel_dig_port =
> +		hdmi_to_dig_port(intel_hdmi);
> +	struct intel_dp *intel_dp = &intel_dig_port->dp;
> +	int type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
> +
> +	if (type != DP_DS_PORT_TYPE_HDMI)
> +		return;
> +
> +	intel_hdmi->dp_to_hdmi.max_tmds_clock =
> +		drm_dp_downstream_max_clock(intel_dp->dpcd,
> +					    intel_dp->downstream_ports);

Poets driven by intel_hdmi don't have DPCD, so I don't know what this
is supposed to achieve.

> +
> +	DRM_DEBUG_KMS("DP HDMI adaptor detected (max TMDS clock : %d kHz\n",
> +		      intel_hdmi->dp_to_hdmi.max_tmds_clock);
> +}
> +
> +static void
>  intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->dev);
> @@ -1438,6 +1463,8 @@ intel_hdmi_set_edid(struct drm_connector *connector, bool force)
>  
>  		intel_hdmi_dp_dual_mode_detect(connector, edid != NULL);
>  
> +		intel_hdmi_dp_adapter_detect(connector);
> +
>  		intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
>  	}
>  
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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