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

[Rodrigo Vivi]

On Wed, Aug 16, 2017 at 11:51 PM 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.


What about downclock modes?!

>

> Also since its a panel, link training should not fail dynamically
> based on cable conditions like in  case of DP.


Is there any bug associated with this patch?


>
> 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)
>  {
>         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,
> --
> 2.1.4
>
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