[Intel-gfx] [PATCH] drm/i915: Do not do link training fallback or prune modes for eDP

[Manasi Navare]

On Thu, Aug 17, 2017 at 12:51:27PM +0300, Jani Nikula wrote:
> On Wed, 16 Aug 2017, Manasi Navare <manasi.d.navare at intel.com> wrote:
> > In case of eDP because the panel has a fixed mode we cannot
> > link train fallback and prune modes since this results in
> > no modes available for eDP connector.
> > Also since its a panel, link training should not fail dynamically
> > based on cable conditions like in  case of DP.
> >
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Jim Bride <jim.bride at linux.intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c               | 2 +-
> >  drivers/gpu/drm/i915/intel_dp_link_training.c | 3 ++-
> >  drivers/gpu/drm/i915/intel_drv.h              | 1 +
> >  3 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 4fd4853..edac0c8 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -109,7 +109,7 @@ static const int default_rates[] = { 162000, 270000, 540000 };
> >   * If a CPU or PCH DP output is attached to an eDP panel, this function
> >   * will return true, and false otherwise.
> >   */
> > -static bool is_edp(struct intel_dp *intel_dp)
> > +bool is_edp(struct intel_dp *intel_dp)
> 
> Make that intel_dp_is_edp when you expose it outside of intel_dp.c
> 
> BR,
> Jani
> 

Yea renaming it as intel_dp_is_edp() makes sense after making it a non static function.
So should I make a seperate patch for this change and changing the name at all places
that call is_edp() currently?

Regards
Manasi

> >  {
> >  	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
> > index 05907fa..18ec61f 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
> > @@ -332,7 +332,8 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
> >  		      intel_connector->base.base.id,
> >  		      intel_connector->base.name,
> >  		      intel_dp->link_rate, intel_dp->lane_count);
> > -	if (!intel_dp_get_link_train_fallback_values(intel_dp,
> > +	/* Dont fallback and prune modes if its eDP */
> > +	if (!is_edp(intel_dp) && !intel_dp_get_link_train_fallback_values(intel_dp,
> >  						     intel_dp->link_rate,
> >  						     intel_dp->lane_count))
> >  		/* Schedule a Hotplug Uevent to userspace to start modeset */
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index fa47285..9800a15 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1548,6 +1548,7 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
> >  }
> >  
> >  bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
> > +bool is_edp(struct intel_dp *intel_dp);
> >  int intel_dp_link_required(int pixel_clock, int bpp);
> >  int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
> >  bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center