[Intel-gfx] [PATCH] drm/i915: Check backlight type while doing eDP backlight initializaiton

[Lee, Shawn C]

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.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Jose Roberto de Souza <jose.souza at intel.com>
Cc: Cooper Chiou <cooper.chiou at intel.com>

Signed-off-by: Lee, Shawn C <shawn.c.lee at 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;
+}
+
 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))
-- 
2.7.4