[Intel-gfx] [PATCH] drm/i915/cnl: Add information to missing case.

[Pandiyan, Dhinakaran]

On Fri, 2017-06-16 at 21:26 +0000, Vivi, Rodrigo wrote:
> On Fri, 2017-06-16 at 21:21 +0000, Pandiyan, Dhinakaran wrote:
> > On Fri, 2017-06-16 at 14:12 -0700, Manasi Navare wrote:
> > > On Fri, Jun 16, 2017 at 08:58:25PM +0000, Pandiyan, Dhinakaran wrote:
> > > > On Fri, 2017-06-16 at 13:20 -0700, Rodrigo Vivi wrote:
> > > > > This missing case could be reached out on missing
> > > > > type or missing voltage.
> > > > 
> > > > Should we even reach this far with a missing DDI type?
> > > > 
> > > > -DK
> > > >
> > > 
> > > Yes it is possible that we get into this situation if reading
> > > of the vccio voltage from PORT_COMP_DW3 returns a garbage value
> > > due to some corruption 
> > 
> > MISSING_CASE already logs that.
> > 
> > > or lets say the type is something that is not
> > > supported on this platform.
> > > 
> > But my question is, should we even be trying to program vswing without
> > knowing the ddi type or for an invalid type? 
> 
> we will reach the return; and avoid vswing programming.
> And logs will give us some information of what failed during modeset.
> 

Correct me if I am wrong, the only callers I could see are
intel_dp_set_signal_levels() and intel_ddi_pre_enable_hdmi(). In both
cases, the encoder type should have been set appropriately. My concern
is that if we are seeing some other type, we should be handling that
before calling cnl_ddi_vswing_program()



> > 
> > > 
> > > > >  So let's add a debug
> > > > > message to make our lives easier whenever this
> > > > > might happen.
> > > > > 
> > > > > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > > > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > > > > ---
> > > > >  drivers/gpu/drm/i915/intel_ddi.c | 1 +
> > > > >  1 file changed, 1 insertion(+)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > > > > index e66947a..c96c8d0 100644
> > > > > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > > > > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > > > > @@ -1802,6 +1802,7 @@ static void cnl_ddi_vswing_program(struct drm_i915_private *dev_priv,
> > > > >  	}
> > > > >  
> > > > >  	if (ddi_translations == NULL) {
> > > > > +		DRM_DEBUG_KMS("Missing DDI translation table for type %d with voltage %d\n", type, voltage);
> > > > >  		MISSING_CASE(voltage);
> > > > >  		return;
> > > > >  	}
> > > 
> > > Like Paulo suggested it would be better to use a switch statement for different vccio voltages
> > > and then have this in the default. What do you think?
> 
> we don't need to iterate on voltages... and the switch for type wouldn't
> catch failures happening inside the functions where we actually pick the
> table.
> 
> > > 
> > > Manasi
> > > 
> > > 
> > > > 
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx at lists.freedesktop.org
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> > 
> 
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