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

[Pandiyan, Dhinakaran]

On Thu, 2017-08-17 at 12:29 -0700, Manasi Navare wrote:
> 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
> 

Don't we already have a intel_dp_is_edp() that checks VBT? That'll need
to be renamed if is_edp() is going to become intel_dp_is_edp() 

Btw I remember seeing Jim's psr patch making this function
global(non-static?) too.


> > >  {
> > >  	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
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