Re: [PATCH] drm/i915: Check backlight type while doing eDP backlight initializaiton

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

On Tue, 18 Jun 2019, "Lee, Shawn C" <shawn.c.lee@intel.com> wrote:
> If LFP backlight type setting from VBT was "VESA eDP AUX Interface".
> Driver should check panel capability and try to initialize aux backlight.
> No matter i915_modparams.enable_dpcd_backlight was enabled or not.

The usual thing to do is to set i915.enable_dpcd_backlight initial value
to -1 (i.e. make it an int), and with that default value respect
VBT. Otherwise, respect the value of enable_dpcd_backlight.

>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Jose Roberto de Souza <jose.souza@intel.com>
> Cc: Cooper Chiou <cooper.chiou@intel.com>
>
> Signed-off-by: Lee, Shawn C <shawn.c.lee@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bios.h             |  1 +
>  drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 11 ++++++++++-
>  2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.h b/drivers/gpu/drm/i915/display/intel_bios.h
> index 4e42cfaf61a7..0b7be6389a07 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.h
> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
> @@ -42,6 +42,7 @@ enum intel_backlight_type {
>  	INTEL_BACKLIGHT_DISPLAY_DDI,
>  	INTEL_BACKLIGHT_DSI_DCS,
>  	INTEL_BACKLIGHT_PANEL_DRIVER_INTERFACE,
> +	INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE,
>  };
>  
>  struct edp_power_seq {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> index 7ded95a334db..0cca5b732ccf 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -261,11 +261,20 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
>  	return false;
>  }
>  
> +static bool
> +intel_dp_bios_use_aux_backlight(struct drm_i915_private *dev_priv)
> +{
> +	if (dev_priv->vbt.backlight.type == INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE)
> +		return true;
> +	return false;
> +}

I think I'd just access dev_priv->vbt.backlight.type directly from
intel_dp_aux_init_backlight_funcs.


BR,
Jani.


> +
>  int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
>  {
>  	struct intel_panel *panel = &intel_connector->panel;
>  
> -	if (!i915_modparams.enable_dpcd_backlight)
> +	if (!i915_modparams.enable_dpcd_backlight &&
> +	    !intel_dp_bios_use_aux_backlight(to_i915(intel_connector->base.dev)))
>  		return -ENODEV;
>  
>  	if (!intel_dp_aux_display_control_capable(intel_connector))

-- 
Jani Nikula, Intel Open Source Graphics Center
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