Re: [PATCH] drm/i915/icl: Add TypeC ports only if VBT is present

[Imre Deak <imre.deak@intel.com>]

On Fri, Jan 25, 2019 at 11:16:08PM +0200, Souza, Jose wrote:
> On Fri, 2019-01-25 at 16:34 +0200, Imre Deak wrote:
> > We can't safely probe Type C ports, whether they are a legacy or a
> > USB/Thunderbolt DP Alternate Type C port. This would require
> > performing
> > the TypeC connect sequence - as described by the specification - but
> > that may have unwanted side-effects. These side-effects include at
> > least
> > - without completeness - timeouts during AUX power well enabling and
> > subsequent PLL enabling errors.
> > 
> 
> Makes sense, behaps there is a bug open with this timeouts and errors
> to link to?

There's no specific bug for these issues as we don't try to detect the
mode.

> 
> > To safely identify these ports we really need VBT, which has the
> > proper
> > flag for this (ddi_vbt_port_info::supports_typec_usb, supports_tbt).
> > Based on the above disable Type C ports if we can't load VBT for some
> > reason.
> 
> 
> Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
> 
> > 
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > Cc: Jose Roberto de Souza <jose.souza@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_bios.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_bios.c
> > b/drivers/gpu/drm/i915/intel_bios.c
> > index 561a4f9f044c..270e7f0ad5cd 100644
> > --- a/drivers/gpu/drm/i915/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/intel_bios.c
> > @@ -1662,10 +1662,12 @@ init_vbt_missing_defaults(struct
> > drm_i915_private *dev_priv)
> >  	for (port = PORT_A; port < I915_MAX_PORTS; port++) {
> >  		struct ddi_vbt_port_info *info =
> >  			&dev_priv->vbt.ddi_port_info[port];
> > +		bool is_tc_port = intel_port_is_tc(dev_priv, port);
> 
> Nit:
> 
> if (intel_port_is_tc(dev_priv, port))
> 	continue;
> 
> instead?

Yep, makes sense, thanks for noticing.

> 
> >  
> > -		info->supports_dvi = (port != PORT_A && port !=
> > PORT_E);
> > +		info->supports_dvi = (port != PORT_A && port != PORT_E
> > &&
> > +				      !is_tc_port);
> >  		info->supports_hdmi = info->supports_dvi;
> > -		info->supports_dp = (port != PORT_E);
> > +		info->supports_dp = (port != PORT_E && !is_tc_port);
> >  	}
> >  }
> >  


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