From 770c12312ad617172b1a65b911d3e6564fc5aca8 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Sat, 11 Aug 2012 08:56:42 +0200 Subject: [PATCH] drm/i915: Fix blank panel at reopening lid When you reopen the lid on a laptop with PCH, the panel suddenly goes blank sometimes. It seems because BLC_PWM_CPU_CTL register is cleared to zero when BLC_PWM_CPU_CTL2 and BLC_PWM_PCH_CTL1 registers are enabled. This patch fixes the problem by moving the call of the function setting BLC_PWM_CPU_CTL after enabling other two registers. Reported-and-tested-by: Hugh Dickins Signed-off-by: Takashi Iwai Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_panel.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 9474488db948..3df4f5fa892a 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -311,9 +311,6 @@ void intel_panel_enable_backlight(struct drm_device *dev, if (dev_priv->backlight_level == 0) dev_priv->backlight_level = intel_panel_get_max_backlight(dev); - dev_priv->backlight_enabled = true; - intel_panel_actually_set_backlight(dev, dev_priv->backlight_level); - if (INTEL_INFO(dev)->gen >= 4) { uint32_t reg, tmp; @@ -326,7 +323,7 @@ void intel_panel_enable_backlight(struct drm_device *dev, * we don't track the backlight dpms state, hence check whether * we have to do anything first. */ if (tmp & BLM_PWM_ENABLE) - return; + goto set_level; if (dev_priv->num_pipe == 3) tmp &= ~BLM_PIPE_SELECT_IVB; @@ -347,6 +344,14 @@ void intel_panel_enable_backlight(struct drm_device *dev, I915_WRITE(BLC_PWM_PCH_CTL1, tmp); } } + +set_level: + /* Call below after setting BLC_PWM_CPU_CTL2 and BLC_PWM_PCH_CTL1. + * BLC_PWM_CPU_CTL may be cleared to zero automatically when these + * registers are set. + */ + dev_priv->backlight_enabled = true; + intel_panel_actually_set_backlight(dev, dev_priv->backlight_level); } static void intel_panel_init_backlight(struct drm_device *dev) -- 2.30.2