Re: [PATCH 6/6 v3] drm/i915: Enable HDMI on DDI-E

From: Daniel Vetter <daniel@ffwll.ch>
To: "Zhang, Xiong Y" <xiong.y.zhang@intel.com>
Cc: "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 6/6 v3] drm/i915: Enable HDMI on DDI-E
Date: Fri, 14 Aug 2015 10:42:00 +0200	[thread overview]
Message-ID: <20150814084200.GN17734@phenom.ffwll.local> (raw)
In-Reply-To: <8082FF9BCB2B054996454E47167FF4EC029C06C7@SHSMSX104.ccr.corp.intel.com>

On Thu, Aug 13, 2015 at 02:57:38AM +0000, Zhang, Xiong Y wrote:
> > On Wed, Aug 12, 2015 at 06:39:34PM +0800, Xiong Zhang wrote:
> > > DDI-E doesn't have the correspondent GMBUS pin.
> > >
> > > We rely on VBT to tell us which one it being used instead.
> > >
> > > The DVI/HDMI on shared port couldn't exist.
> > >
> > > This patch isn't tested without hardware wchich has HDMI on DDI-E.
> > >
> > > v2: fix trailing whitespace
> > > v3: WARN() take place of BUG()
> > 
> > I asked for MISSING_CASE, not WARN.
> > -Daniel
> [Zhang, Xiong Y] Because DDI-E on SKL doesn't have correspondent GMBUS pin, it should share such pin with DDI-B/C/D. We don't know the default GMBUS pin for DDI-E if VBT doesn't tell us. 
> If VBT don't tell us or give us an invalid GMBUS pin, driver will fail in getting HDMI info. In such case, we really need a warn which tell us why driver couldn't read EDID info for HDMI on DDI-E.

Have you bothered to look at the MISSING_CASE macro?! It does boil down to
a WARN, but I prefer it much over a WARN_ON since it's nicely
standardized.

Thanks, Daniel

> 
> thanks
> > 
> > >
> > > Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
> > > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/i915_drv.h   |  5 +++++
> > >  drivers/gpu/drm/i915/intel_bios.c | 25 +++++++++++++++++++++----
> > > drivers/gpu/drm/i915/intel_hdmi.c | 18 ++++++++++++++++++
> > >  3 files changed, 44 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > > b/drivers/gpu/drm/i915/i915_drv.h index 6d93334..5d8e7fe 100644
> > > --- a/drivers/gpu/drm/i915/i915_drv.h
> > > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > > @@ -1414,6 +1414,10 @@ enum modeset_restore {  #define DP_AUX_C
> > 0x20
> > > #define DP_AUX_D 0x30
> > >
> > > +#define DDC_PIN_B  0x05
> > > +#define DDC_PIN_C  0x04
> > > +#define DDC_PIN_D  0x06
> > > +
> > >  struct ddi_vbt_port_info {
> > >  	/*
> > >  	 * This is an index in the HDMI/DVI DDI buffer translation table.
> > > @@ -1428,6 +1432,7 @@ struct ddi_vbt_port_info {
> > >  	uint8_t supports_dp:1;
> > >
> > >  	uint8_t alternate_aux_channel;
> > > +	uint8_t alternate_ddc_pin;
> > >  };
> > >
> > >  enum psr_lines_to_wait {
> > > diff --git a/drivers/gpu/drm/i915/intel_bios.c
> > > b/drivers/gpu/drm/i915/intel_bios.c
> > > index 16cdf17..8140531 100644
> > > --- a/drivers/gpu/drm/i915/intel_bios.c
> > > +++ b/drivers/gpu/drm/i915/intel_bios.c
> > > @@ -894,7 +894,7 @@ static void parse_ddi_port(struct drm_i915_private
> > *dev_priv, enum port port,
> > >  	uint8_t hdmi_level_shift;
> > >  	int i, j;
> > >  	bool is_dvi, is_hdmi, is_dp, is_edp, is_crt;
> > > -	uint8_t aux_channel;
> > > +	uint8_t aux_channel, ddc_pin;
> > >  	/* Each DDI port can have more than one value on the "DVO Port" field,
> > >  	 * so look for all the possible values for each port and abort if more
> > >  	 * than one is found. */
> > > @@ -928,6 +928,7 @@ static void parse_ddi_port(struct drm_i915_private
> > *dev_priv, enum port port,
> > >  		return;
> > >
> > >  	aux_channel = child->raw[25];
> > > +	ddc_pin = child->common.ddc_pin;
> > >
> > >  	is_dvi = child->common.device_type &
> > DEVICE_TYPE_TMDS_DVI_SIGNALING;
> > >  	is_dp = child->common.device_type &
> > DEVICE_TYPE_DISPLAYPORT_OUTPUT;
> > > @@ -959,11 +960,27 @@ static void parse_ddi_port(struct
> > drm_i915_private *dev_priv, enum port port,
> > >  		DRM_DEBUG_KMS("Port %c is internal DP\n", port_name(port));
> > >
> > >  	if (is_dvi) {
> > > -		if (child->common.ddc_pin == 0x05 && port != PORT_B)
> > > +		if (port == PORT_E) {
> > > +			info->alternate_ddc_pin = ddc_pin;
> > > +			/* if DDIE share ddc pin with other port, then
> > > +			 * dvi/hdmi couldn't exist on the shared port.
> > > +			 * Otherwise they share the same ddc bin and system
> > > +			 * couldn't communicate with them seperately. */
> > > +			if (ddc_pin == DDC_PIN_B) {
> > > +				dev_priv->vbt.ddi_port_info[PORT_B].supports_dvi = 0;
> > > +				dev_priv->vbt.ddi_port_info[PORT_B].supports_hdmi = 0;
> > > +			} else if (ddc_pin == DDC_PIN_C) {
> > > +				dev_priv->vbt.ddi_port_info[PORT_C].supports_dvi = 0;
> > > +				dev_priv->vbt.ddi_port_info[PORT_C].supports_hdmi = 0;
> > > +			} else if (ddc_pin == DDC_PIN_D) {
> > > +				dev_priv->vbt.ddi_port_info[PORT_D].supports_dvi = 0;
> > > +				dev_priv->vbt.ddi_port_info[PORT_D].supports_hdmi = 0;
> > > +			}
> > > +		} else if (ddc_pin == DDC_PIN_B && port != PORT_B)
> > >  			DRM_DEBUG_KMS("Unexpected DDC pin for port B\n");
> > > -		if (child->common.ddc_pin == 0x04 && port != PORT_C)
> > > +		else if (ddc_pin == DDC_PIN_C && port != PORT_C)
> > >  			DRM_DEBUG_KMS("Unexpected DDC pin for port C\n");
> > > -		if (child->common.ddc_pin == 0x06 && port != PORT_D)
> > > +		else if (ddc_pin == DDC_PIN_D && port != PORT_D)
> > >  			DRM_DEBUG_KMS("Unexpected DDC pin for port D\n");
> > >  	}
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
> > > b/drivers/gpu/drm/i915/intel_hdmi.c
> > > index 70bad5b..a4129f2 100644
> > > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > > @@ -1991,6 +1991,24 @@ void intel_hdmi_init_connector(struct
> > intel_digital_port *intel_dig_port,
> > >  			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. */
> > > +		switch (dev_priv->vbt.ddi_port_info[PORT_E].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:
> > > +			WARN(1, "VBT assign invalid DDC PIN for	HDMI on
> > PORT_E.\n");
> > > +		}
> > > +		intel_encoder->hpd_pin = HPD_PORT_E;
> > > +		break;
> > >  	case PORT_A:
> > >  		intel_encoder->hpd_pin = HPD_PORT_A;
> > >  		/* Internal port only for eDP. */
> > > --
> > > 2.1.4
> > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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