Child min_brightness is obsolete from VBT 234+, instead the new
min_brightness field in the main structure should be used.
This new field is 16 bits wide, so backlight_precision_bits is needed
to check if value needs to be scaled down but it is only available in
VBT 236+ so working around it by using the also new backlight_level
in the main struct.
v2:
- missed that backlight_data->level is also obsolete
v3:
- s/backlight/brightness to better match specification
- using u16 to specify brightness level instead of a u32 : 16
BSpec: 20149
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_bios.c | 30 +++++++++++++++++--
drivers/gpu/drm/i915/display/intel_vbt_defs.h | 12 ++++++--
2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 5804eb9faf24..b4d99d0bf696 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -425,6 +425,7 @@ parse_lfp_backlight(struct drm_i915_private *dev_priv,
const struct bdb_lfp_backlight_data *backlight_data;
const struct lfp_backlight_data_entry *entry;
int panel_type = dev_priv->vbt.panel_type;
+ u16 level;
backlight_data = find_section(bdb, BDB_LVDS_BACKLIGHT);
if (!backlight_data)
@@ -459,14 +460,39 @@ parse_lfp_backlight(struct drm_i915_private *dev_priv,
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;
+
+ if (bdb->version >= 234) {
+ u16 min_level;
+ bool scale;
+
+ level = backlight_data->brightness_level[panel_type].level;
+ min_level = backlight_data->brightness_min_level[panel_type].level;
+
+ if (bdb->version >= 236)
+ scale = backlight_data->brightness_precision_bits[panel_type] == 16;
+ else
+ scale = level > 255;
+
+ if (scale)
+ min_level = min_level / 255;
+
+ if (min_level > 255) {
+ drm_warn(&dev_priv->drm, "Brightness min level > 255\n");
+ level = 255;
+ }
+ dev_priv->vbt.backlight.min_brightness = min_level;
+ } else {
+ level = backlight_data->level[panel_type];
+ dev_priv->vbt.backlight.min_brightness = entry->min_brightness;
+ }
+
drm_dbg_kms(&dev_priv->drm,
"VBT backlight PWM modulation frequency %u Hz, "
"active %s, min brightness %u, level %u, controller %u\n",
dev_priv->vbt.backlight.pwm_freq_hz,
dev_priv->vbt.backlight.active_low_pwm ? "low" : "high",
dev_priv->vbt.backlight.min_brightness,
- backlight_data->level[panel_type],
+ level,
dev_priv->vbt.backlight.controller);
}
diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
index 54bcc6a6947c..5df23e1848a6 100644
--- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
@@ -782,7 +782,7 @@ struct lfp_backlight_data_entry {
u8 active_low_pwm:1;
u8 obsolete1:5;
u16 pwm_freq_hz;
- u8 min_brightness;
+ u8 min_brightness; /* Obsolete from 234+ */
u8 obsolete2;
u8 obsolete3;
} __packed;
@@ -792,11 +792,19 @@ struct lfp_backlight_control_method {
u8 controller:4;
} __packed;
+struct lfp_brightness_level {
+ u16 level;
+ u16 reserved;
+} __packed;
+
struct bdb_lfp_backlight_data {
u8 entry_size;
struct lfp_backlight_data_entry data[16];
- u8 level[16];
+ u8 level[16]; /* Obsolete from 234+ */
struct lfp_backlight_control_method backlight_control[16];
+ struct lfp_brightness_level brightness_level[16]; /* 234+ */
+ struct lfp_brightness_level brightness_min_level[16]; /* 234+ */
+ u8 brightness_precision_bits[16]; /* 236+ */
} __packed;
/*
--
2.28.0
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
