diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index bb8612ab8ee1..beca98d2b035 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -1496,8 +1496,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus { struct drm_i915_private *dev_priv = to_i915(connector->base.dev); struct intel_panel *panel = &connector->panel; - u32 pch_ctl1, pch_ctl2, val; - bool alt; + u32 cpu_ctl2, pch_ctl1, pch_ctl2, val; + bool alt, cpu_mode; if (HAS_PCH_LPT(dev_priv)) alt = I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY; @@ -1511,6 +1511,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2); panel->backlight.max = pch_ctl2 >> 16; + cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2); + if (!panel->backlight.max) panel->backlight.max = get_backlight_max_vbt(connector); @@ -1519,12 +1521,28 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus panel->backlight.min = get_backlight_min_vbt(connector); - val = lpt_get_backlight(connector); + panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE; + + cpu_mode = panel->backlight.enabled && HAS_PCH_LPT(dev_priv) && + !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) && + (cpu_ctl2 & BLM_PWM_ENABLE); + if (cpu_mode) + val = pch_get_backlight(connector); + else + val = lpt_get_backlight(connector); val = intel_panel_compute_brightness(connector, val); panel->backlight.level = clamp(val, panel->backlight.min, panel->backlight.max); - panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE; + if (cpu_mode) { + DRM_DEBUG_KMS("CPU backlight register was enabled, switching to PCH override\n"); + + /* Write converted CPU PWM value to PCH override register */ + lpt_set_backlight(connector->base.state, panel->backlight.level); + I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE); + + I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2 & ~BLM_PWM_ENABLE); + } return 0; }