diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index acf8aec..ef4744e 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -203,7 +203,13 @@
 	algo->data = bus;
 }
 
-#define HAS_GMBUS_IRQ(dev) (INTEL_INFO(dev)->gen >= 4)
+/*
+ * gmbus on gen4 seems to be able to generate legacy interrupts even when in MSI
+ * mode. This results in spurious interrupt warnings if the legacy irq no. is
+ * shared with another device. The kernel then disables that interrupt source
+ * and so prevents the other device from working properly.
+ */
+#define HAS_GMBUS_IRQ(dev) (INTEL_INFO(dev)->gen >= 5)
 static int
 gmbus_wait_hw_status(struct drm_i915_private *dev_priv,
 		     u32 gmbus2_status,
@@ -214,6 +220,9 @@
 	u32 gmbus2 = 0;
 	DEFINE_WAIT(wait);
 
+	if (!HAS_GMBUS_IRQ(dev_priv->dev))
+		gmbus4_irq_en = 0;
+
 	/* Important: The hw handles only the first bit, so set only one! Since
 	 * we also need to check for NAKs besides the hw ready/idle signal, we
 	 * need to wake up periodically and check that ourselves. */