From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 9 Apr 2014 08:22:06 +0000 (+0300)
Subject: drm/i915: check VBT for supported backlight type
X-Git-Tag: Ubuntu-snapdragon-4.4.0-1029.32~8846^2~11^2~2
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=39fbc9c8f6765959b55e0b127dd5c57df5a47d67;p=mirror_ubuntu-zesty-kernel.git

drm/i915: check VBT for supported backlight type

The only supported types are none and PWM. Other values are obsolete or
reserved, don't add them.

Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Martin <bugs@mrvanes.com>
Tested-by: jrg.otte@gmail.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0905cd915589..d24eba70ca9f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1308,6 +1308,7 @@ struct intel_vbt_data {
 
 	struct {
 		u16 pwm_freq_hz;
+		bool present;
 		bool active_low_pwm;
 	} backlight;
 
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 4867f4cc0938..fa486c5fbb02 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -287,6 +287,9 @@ parse_lfp_backlight(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 	const struct bdb_lfp_backlight_data *backlight_data;
 	const struct bdb_lfp_backlight_data_entry *entry;
 
+	/* Err to enabling backlight if no backlight block. */
+	dev_priv->vbt.backlight.present = true;
+
 	backlight_data = find_section(bdb, BDB_LVDS_BACKLIGHT);
 	if (!backlight_data)
 		return;
@@ -299,6 +302,13 @@ parse_lfp_backlight(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 
 	entry = &backlight_data->data[panel_type];
 
+	dev_priv->vbt.backlight.present = entry->type == BDB_BACKLIGHT_TYPE_PWM;
+	if (!dev_priv->vbt.backlight.present) {
+		DRM_DEBUG_KMS("PWM backlight not present in VBT (type %u)\n",
+			      entry->type);
+		return;
+	}
+
 	dev_priv->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;
 	dev_priv->vbt.backlight.active_low_pwm = entry->active_low_pwm;
 	DRM_DEBUG_KMS("VBT backlight PWM modulation frequency %u Hz, "
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 83b7629e4367..f27f7b282465 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -374,6 +374,9 @@ struct bdb_lvds_lfp_data {
 	struct bdb_lvds_lfp_data_entry data[16];
 } __packed;
 
+#define BDB_BACKLIGHT_TYPE_NONE	0
+#define BDB_BACKLIGHT_TYPE_PWM	2
+
 struct bdb_lfp_backlight_data_entry {
 	u8 type:2;
 	u8 active_low_pwm:1;