Comment 69 for bug 1488719

However this helps. We're missing something.

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 76bd40e13391..0d524034abd7 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1827,6 +1827,9 @@ static void ibx_hpd_irq_handler(struct drm_device *dev, u32 hotplug_trigger,
        dig_hotplug_reg = I915_READ(PCH_PORT_HOTPLUG);
        I915_WRITE(PCH_PORT_HOTPLUG, dig_hotplug_reg);

+ if (!hotplug_trigger)
+ return;
+
        intel_get_hpd_pins(&pin_mask, &long_mask, hotplug_trigger,
                           dig_hotplug_reg, hpd,
                           pch_port_hotplug_long_detect);
@@ -1934,8 +1937,7 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
        int pipe;
        u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;

- if (hotplug_trigger)
- ibx_hpd_irq_handler(dev, hotplug_trigger, hpd_cpt);
+ ibx_hpd_irq_handler(dev, hotplug_trigger, hpd_cpt);

        if (pch_iir & SDE_AUDIO_POWER_MASK_CPT) {
                int port = ffs((pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>