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Commit 770c1231 authored by Takashi Iwai's avatar Takashi Iwai Committed by Daniel Vetter
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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: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 9830605d

drivers/gpu/drm/i915/intel_panel.c

+9 −4
Original line number Diff line number Diff line
@@ -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)