From a644ca9bcdac3b9e9f0fd2726c9198e85cecfbee Mon Sep 17 00:00:00 2001
From: Puthikorn Voravootivat <puthik@chromium.org>
Date: Thu, 11 May 2017 16:02:17 -0700
Subject: [PATCH] drm/i915: Fix cap check for intel_dp_aux_backlight driver
Git-commit: a644ca9bcdac3b9e9f0fd2726c9198e85cecfbee
Patch-mainline: v4.13-rc1
References: FATE#322643 bsc#1055900

intel_dp_aux_backlight driver should check for the
DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP before enable the driver.

Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170511230225.142870-2-puthik@chromium.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/intel_dp_aux_backlight.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -142,6 +142,7 @@ intel_dp_aux_display_control_capable(str
 	 */
 	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
 	    (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
+	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
 	    !((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
 	      (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
 		DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");