drm/i915: extract backlight minimum brightness from VBT

Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1270,6 +1270,7 @@ struct intel_vbt_data {
 		u16 pwm_freq_hz;
 		bool present;
 		bool active_low_pwm;
+		u8 min_brightness;	/* min_brightness/255 of max */
 	} backlight;
 
 	/* MIPI DSI */

drivers/gpu/drm/i915/intel_bios.c

@@ -336,11 +336,12 @@ parse_lfp_backlight(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 
 	dev_priv->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;
 	dev_priv->vbt.backlight.active_low_pwm = entry->active_low_pwm;
+	dev_priv->vbt.backlight.min_brightness = entry->min_brightness;
 	DRM_DEBUG_KMS("VBT backlight PWM modulation frequency %u Hz, "
 		      "active %s, min brightness %u, level %u\n",
 		      dev_priv->vbt.backlight.pwm_freq_hz,
 		      dev_priv->vbt.backlight.active_low_pwm ? "low" : "high",
-		      entry->min_brightness,
+		      dev_priv->vbt.backlight.min_brightness,
 		      backlight_data->level[panel_type]);
 }