From ac73661c6222faef1a97ec44f424234f165e4710 Mon Sep 17 00:00:00 2001
From: "Lee, Shawn C" <shawn.c.lee@intel.com>
Date: Tue, 12 Sep 2017 11:36:30 +0800
Subject: [PATCH] drm/i915/bxt: set min brightness from VBT
Git-commit: ac73661c6222faef1a97ec44f424234f165e4710
Patch-mainline: v4.14-rc2
References: FATE#322643 bsc#1055900
No-fix: c3881128cb672cf484a52fbb36b5daa9044d9168

Min brightness value from vbt was missing for BXT platform.
This setting have to refer backlight ic spec to restrict
min backlight output. Without this restriction, driver would
allow to configure lower brightness value and violate
backlight ic requirement.

Fixes: 0fb890c01349 ("drm/i915/bxt: BLC implementation")
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: Gary C Wang <gary.c.wang@intel.com>
Signed-off-by: Shawn Lee <shawn.c.lee@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1505187390-7039-1-git-send-email-shawn.c.lee@intel.com
(cherry picked from commit c3881128cb672cf484a52fbb36b5daa9044d9168)

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/intel_panel.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1699,6 +1699,8 @@ bxt_setup_backlight(struct intel_connect
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	panel->backlight.min = get_backlight_min_vbt(connector);
+
 	val = bxt_get_backlight(connector);
 	val = intel_panel_compute_brightness(connector, val);
 	panel->backlight.level = clamp(val, panel->backlight.min,