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 0905cd915589a8fe2e122cf73c50516b313b9148..d24eba70ca9f107b1f3356e44a5a98ebbe943d8c 100644 (file)
--- 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 4867f4cc0938cba2db4a33bfdb464712defa5e9c..fa486c5fbb0250650b558632c6f63aa0ebf5bd63 100644 (file)
--- 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 83b7629e4367bdac9a992f1c63d684074c8ef10f..f27f7b282465aa76a77690ebe8239775c923f06e 100644 (file)
--- 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;