From 39fbc9c8f6765959b55e0b127dd5c57df5a47d67 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 9 Apr 2014 11:22:06 +0300
Subject: [PATCH] drm/i915: check VBT for supported backlight type
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/intel_bios.c | 10 ++++++++++
drivers/gpu/drm/i915/intel_bios.h | 3 +++
3 files changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0905cd915589a..d24eba70ca9f1 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 4867f4cc0938c..fa486c5fbb025 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 83b7629e4367b..f27f7b282465a 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;
--
GitLab