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

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 16 Aug 2017, Manasi Navare <manasi.d.navare@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@linux.intel.com>
> Cc: Jim Bride <jim.bride@linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare@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

>  {
>  	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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