[Intel-gfx] [PATCH 09/10] drm/i915: Unify error handling for missing DDI buf trans tables

[Ville Syrjälä]

On Wed, Oct 18, 2017 at 10:41:44AM -0700, James Ausmus wrote:
> On Mon, Oct 16, 2017 at 05:57:04PM +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Handle missing buf trans tables, or out of bounds buf trans levels
> > the same way everywhere. These should never be hit under normal
> > conditions, but let's play it safe for now.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c | 25 ++++++++++++++++++++-----
> >  1 file changed, 20 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index f0a709b66e00..5f1c546e5e61 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -801,6 +801,9 @@ static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port por
> >  	    hdmi_level >= n_hdmi_entries)
> >  		hdmi_level = hdmi_default_entry;
> >  
> > +	if (WARN_ON_ONCE(hdmi_level >= n_hdmi_entries))
> > +		hdmi_level = n_hdmi_entries - 1;
> 
> intel_ddi_get_buf_trans_* can set n_entries to 0 on failure,
> which would cause this to return a level of -1 - maybe those functions
> need to return 1 on failure instead, similar to the cnl_get_buf_trans_*
> functions?

Hmm. I guess we could just do

if (WARN_ON(hdmi_level == 0))
	return;

before the other check. That would be equivalent to the
!ddi_translations checks done in the other places.

> 
> > +
> >  	return hdmi_level;
> >  }
> >  
> > @@ -864,6 +867,11 @@ static void intel_prepare_hdmi_ddi_buffers(struct intel_encoder *encoder,
> >  
> >  	ddi_translations_hdmi = intel_ddi_get_buf_trans_hdmi(dev_priv, &n_hdmi_entries);
> >  
> > +	if (WARN_ON_ONCE(!ddi_translations_hdmi))
> > +		return;
> > +	if (WARN_ON_ONCE(hdmi_level >= n_hdmi_entries))
> > +		hdmi_level = n_hdmi_entries - 1;
> > +
> >  	/* If we're boosting the current, set bit 31 of trans1 */
> >  	if (IS_GEN9_BC(dev_priv) &&
> >  	    dev_priv->vbt.ddi_port_info[port].hdmi_boost_level)
> > @@ -1847,6 +1855,11 @@ static void skl_ddi_set_iboost(struct intel_encoder *encoder,
> >  		else
> >  			ddi_translations = intel_ddi_get_buf_trans_dp(dev_priv, port, &n_entries);
> >  
> > +		if (WARN_ON_ONCE(!ddi_translations))
> > +			return;
> > +		if (WARN_ON_ONCE(level >= n_entries))
> > +			level = n_entries - 1;
> 
> 
> > +
> >  		iboost = ddi_translations[level].i_boost;
> >  	}
> >  
> > @@ -1877,6 +1890,11 @@ static void bxt_ddi_vswing_sequence(struct intel_encoder *encoder,
> >  	else
> >  		ddi_translations = bxt_get_buf_trans_dp(dev_priv, &n_entries);
> >  
> > +	if (WARN_ON_ONCE(!ddi_translations))
> > +		return;
> > +	if (WARN_ON_ONCE(level >= n_entries))
> > +		level = n_entries - 1;
> > +
> >  	bxt_ddi_phy_set_signal_level(dev_priv, port,
> >  				     ddi_translations[level].margin,
> >  				     ddi_translations[level].scale,
> > @@ -1932,13 +1950,10 @@ static void cnl_ddi_vswing_program(struct intel_encoder *encoder,
> >  	else
> >  		ddi_translations = cnl_get_buf_trans_dp(dev_priv, &n_entries);
> >  
> > -	if (WARN_ON(ddi_translations == NULL))
> > +	if (WARN_ON_ONCE(!ddi_translations))
> >  		return;
> > -
> > -	if (level >= n_entries) {
> > -		DRM_DEBUG_KMS("DDI translation not found for level %d. Using %d instead.", level, n_entries - 1);
> > +	if (WARN_ON_ONCE(level >= n_entries))
> >  		level = n_entries - 1;
> > -	}
> >  
> >  	/* Set PORT_TX_DW5 Scaling Mode Sel to 010b. */
> >  	val = I915_READ(CNL_PORT_TX_DW5_LN0(port));
> > -- 
> > 2.13.6
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC