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drm/i915/vbt: Fix backlight parsing for VBT 234+

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Child min_brightness is obsolete from VBT 234+, instead the new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@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201008211932.24989-1-jose.souza@intel.com
This commit is contained in:
José Roberto de Souza 2020-10-08 14:19:30 -07:00
parent 63b9d9aa85
commit d381baad29
2 changed files with 38 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/gpu/drm/i915/display/intel_bios.c
View File

@ -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);
}

12
drivers/gpu/drm/i915/display/intel_vbt_defs.h
View File

@ -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;
/*