So far, DCS backlight driver hardcode (0xFF) for max brightness level.
MIPI DCS spec allow max 0xFFFF for set_display_brightness (51h) command.
And VBT brightness precision bits can support 8 ~ 16 bits.
We should set correct precision bits in VBT that meet panel's request.
Driver can refer to this setting then configure max brightness level
in DCS backlight driver properly.
v2: modify variable name brightness_precision_bits instead of
max_brightness_level.
v3: fix checkpatch warning.
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Vandita Kulkarni <vandita.kulkarni@xxxxxxxxx>
Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx>
Cc: William Tseng <william.tseng@xxxxxxxxx>
Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_bios.c | 3 +++
drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c | 10 ++++++++--
drivers/gpu/drm/i915/i915_drv.h | 1 +
3 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index e86e6ed2d3bf..ccaf0a3100f7 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -483,6 +483,9 @@ parse_lfp_backlight(struct drm_i915_private *i915,
level = 255;
}
i915->vbt.backlight.min_brightness = min_level;
+
+ i915->vbt.backlight.brightness_precision_bits =
+ backlight_data->brightness_precision_bits[panel_type];
} else {
level = backlight_data->level[panel_type];
i915->vbt.backlight.min_brightness = entry->min_brightness;
diff --git a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
index 584c14c4cbd0..567c086602d5 100644
--- a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
@@ -147,10 +147,16 @@ static void dcs_enable_backlight(const struct intel_crtc_state *crtc_state,
static int dcs_setup_backlight(struct intel_connector *connector,
enum pipe unused)
{
+ struct drm_device *dev = connector->base.dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
struct intel_panel *panel = &connector->panel;
- panel->backlight.max = PANEL_PWM_MAX_VALUE;
- panel->backlight.level = PANEL_PWM_MAX_VALUE;
+ if (dev_priv->vbt.backlight.brightness_precision_bits > 8)
+ panel->backlight.max = (1 << dev_priv->vbt.backlight.brightness_precision_bits) - 1;
+ else
+ panel->backlight.max = PANEL_PWM_MAX_VALUE;
+
+ panel->backlight.level = panel->backlight.max;
return 0;
}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index be2392bbcecc..99a2d308b24d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -705,6 +705,7 @@ struct intel_vbt_data {
struct {
u16 pwm_freq_hz;
+ u16 brightness_precision_bits;
bool present;
bool active_low_pwm;
u8 min_brightness; /* min_brightness/255 of max */
--
2.17.1
