Re: [Intel-gfx] [PATCH 2/4] drm/i915: Respect alternate_ddc_pin for all DDI ports

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Jim Bride <jim.bride@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org,
	Maarten Maathuis <madman2003@gmail.com>,
	stable@vger.kernel.org
Subject: Re: [Intel-gfx] [PATCH 2/4] drm/i915: Respect alternate_ddc_pin for all DDI ports
Date: Thu, 13 Oct 2016 21:29:30 +0300	[thread overview]
Message-ID: <20161013182930.GS4329@intel.com> (raw)
In-Reply-To: <20161013180654.GE4042@shiv>

On Thu, Oct 13, 2016 at 11:06:55AM -0700, Jim Bride wrote:
> On Tue, Oct 11, 2016 at 08:52:46PM +0300, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjï¿½lï¿½ <ville.syrjala@linux.intel.com>
> > 
> > The VBT provides the platform a way to mix and match the DDI ports vs.
> > GMBUS pins. Currently we only trust the VBT for DDI E, which I suppose
> > has no standard GMBUS pin assignment. However, there are machines out
> > there that use a non-standard mapping for the other ports as well.
> > Let's start trusting the VBT on this one for all ports on DDI platforms.
> > 
> > I've structured the code such that other platforms could easily start
> > using this as well, by simply filling in the ddi_port_info. IIRC there
> > may be CHV system that might actually need this.
> > 
> > v2: Include a commit message, include a debug message during init
> > 
> > Cc: stable@vger.kernel.org
> > Cc: Maarten Maathuis <madman2003@gmail.com>
> > Tested-by: Maarten Maatt show huis <madman2003@gmail.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97877
> > Signed-off-by: Ville Syrjï¿½lï¿½ <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_hdmi.c | 84 ++++++++++++++++++++++-----------------
> >  1 file changed, 48 insertions(+), 36 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> > index 8d46f5836746..9ca86e901fc8 100644
> > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > @@ -1799,6 +1799,50 @@ intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct drm_connector *c
> >  	intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
> >  }
> >  
> > +static u8 intel_hdmi_ddc_pin(struct drm_i915_private *dev_priv,
> > +			     enum port port)
> > +{
> > +	const struct ddi_vbt_port_info *info =
> > +		&dev_priv->vbt.ddi_port_info[port];
> > +	u8 ddc_pin;
> > +
> > +	if (info->alternate_ddc_pin) {
> > +		DRM_DEBUG_KMS("Using DDC pin 0x%x for port %c (VBT)\n",
> > +			      info->alternate_ddc_pin, port_name(port));
> > +		return info->alternate_ddc_pin;
> > +	}
> > +
> > +	switch (port) {
> > +	case PORT_B:
> > +		if (IS_BROXTON(dev_priv))
> > +			ddc_pin = GMBUS_PIN_1_BXT;
> > +		else
> > +			ddc_pin = GMBUS_PIN_DPB;
> > +		break;
> > +	case PORT_C:
> > +		if (IS_BROXTON(dev_priv))
> > +			ddc_pin = GMBUS_PIN_2_BXT;
> > +		else
> > +			ddc_pin = GMBUS_PIN_DPC;
> > +		break;
> > +	case PORT_D:
> > +		if (IS_CHERRYVIEW(dev_priv))
> > +			ddc_pin = GMBUS_PIN_DPD_CHV;
> > +		else
> > +			ddc_pin = GMBUS_PIN_DPD;
> 
> In the code removed below there's a specific case covering Broxton that
> isn't accounted for here.  Are we sure that we don't need that logic here?

Yeah, BXT doesn't have port D.

I guess we could split this up into a few platform specific functions that
could then have the MISSING_CASE() for the impossible ports. A bit like
the AUX ctl/data register setup functions we have. Do pople want that
level of paranoia here?

> 
> Jim
> 
> > +		break;
> > +	default:
> > +		MISSING_CASE(port);
> > +		ddc_pin = GMBUS_PIN_DPB;
> > +		break;
> > +	}
> > +
> > +	DRM_DEBUG_KMS("Using DDC pin 0x%x for port %c (platform default)\n",
> > +		      ddc_pin, port_name(port));
> > +
> > +	return ddc_pin;
> > +}
> > +
> >  void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
> >  			       struct intel_connector *intel_connector)
> >  {
> > @@ -1808,7 +1852,6 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
> >  	struct drm_device *dev = intel_encoder->base.dev;
> >  	struct drm_i915_private *dev_priv = to_i915(dev);
> >  	enum port port = intel_dig_port->port;
> > -	uint8_t alternate_ddc_pin;
> >  
> >  	DRM_DEBUG_KMS("Adding HDMI connector on port %c\n",
> >  		      port_name(port));
> > @@ -1826,12 +1869,10 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
> >  	connector->doublescan_allowed = 0;
> >  	connector->stereo_allowed = 1;
> >  
> > +	intel_hdmi->ddc_bus = intel_hdmi_ddc_pin(dev_priv, port);
> > +
> >  	switch (port) {
> >  	case PORT_B:
> > -		if (IS_BROXTON(dev_priv))
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_1_BXT;
> > -		else
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPB;
> >  		/*
> >  		 * On BXT A0/A1, sw needs to activate DDIA HPD logic and
> >  		 * interrupts to check the external panel connection.
> > @@ -1842,46 +1883,17 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
> >  			intel_encoder->hpd_pin = HPD_PORT_B;
> >  		break;
> >  	case PORT_C:
> > -		if (IS_BROXTON(dev_priv))
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_2_BXT;
> > -		else
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPC;
> >  		intel_encoder->hpd_pin = HPD_PORT_C;
> >  		break;
> >  	case PORT_D:
> > -		if (WARN_ON(IS_BROXTON(dev_priv)))
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DISABLED;
> > -		else if (IS_CHERRYVIEW(dev_priv))
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPD_CHV;
> > -		else
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPD;
> >  		intel_encoder->hpd_pin = HPD_PORT_D;
> >  		break;
> >  	case PORT_E:
> > -		/* On SKL PORT E doesn't have seperate GMBUS pin
> > -		 *  We rely on VBT to set a proper alternate GMBUS pin. */
> > -		alternate_ddc_pin =
> > -			dev_priv->vbt.ddi_port_info[PORT_E].alternate_ddc_pin;
> > -		switch (alternate_ddc_pin) {
> > -		case DDC_PIN_B:
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPB;
> > -			break;
> > -		case DDC_PIN_C:
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPC;
> > -			break;
> > -		case DDC_PIN_D:
> > -			intel_hdmi->ddc_bus = GMBUS_PIN_DPD;
> > -			break;
> > -		default:
> > -			MISSING_CASE(alternate_ddc_pin);
> > -		}
> >  		intel_encoder->hpd_pin = HPD_PORT_E;
> >  		break;
> > -	case PORT_A:
> > -		intel_encoder->hpd_pin = HPD_PORT_A;
> > -		/* Internal port only for eDP. */
> >  	default:
> > -		BUG();
> > +		MISSING_CASE(port);
> > +		return;
> >  	}
> >  
> >  	if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) {
> > -- 
> > 2.7.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjï¿½lï¿½
Intel OTC