From 8c7a758873577f0d1bb3f879584338f73e6c6bc3 Mon Sep 17 00:00:00 2001
From: "Lee, Shawn C" <shawn.c.lee@intel.com>
Date: Wed, 13 Sep 2017 13:19:20 +0800
Subject: [PATCH] drm/i915/cnp: set min brightness from VBT
Git-commit: 8c7a758873577f0d1bb3f879584338f73e6c6bc3
Patch-mainline: v4.14-rc2
References: FATE#322643 bsc#1055900
No-fix: f44e354f857f207cd361269c5e38e1f96e0b616c

Min brightness value from vbt was missing for CNP 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: 4c9f7086ac6d ("drm/i915/cnp: Backlight support for CNP.")
Cc: Jani Nikula <jani.nikula@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/1505279961-16140-1-git-send-email-shawn.c.lee@intel.com
(cherry picked from commit f44e354f857f207cd361269c5e38e1f96e0b616c)

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
@@ -1737,6 +1737,8 @@ cnp_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,