drm/i915: fix user irq miss in BSD ring on g4x

On g4x, user interrupt in BSD ring is missed.
This is because though g4x and ironlake share the same bsd_ring,
their interrupt control interfaces have _two_ differences.

1.different irq enable/disable functions:
On g4x are i915_enable_irq and i915_disable_irq.
On ironlake are ironlake_enable_irq and ironlake_disable_irq.
2.different irq flag:
On g4x user interrupt flag in BSD ring on is I915_BSD_USER_INTERRUPT.
On ironlake is GT_BSD_USER_INTERRUPT

Old bsd_ring_get/put_irq call ring_get_irq and ring_get_irq.
ring_get_irq and ring_put_irq only call ironlake_enable/disable_irq.
So comes the irq miss on g4x.

To fix this, as other rings' code do, conditionally call different
functions(i915_enable/disable_irq and ironlake_enable/disable_irq)
and use different interrupt flags in bsd_ring_get/put_irq.

Signed-off-by: Feng, Boqun <boqun.feng@intel.com>
Reviewed-by: Xiang, Haihao <haihao.xiang@intel.com>
Cc: stable@kernel.org
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -687,12 +687,37 @@ gen6_ring_put_irq(struct intel_ring_buffer *ring, u32 gflag, u32 rflag)
 static bool
 bsd_ring_get_irq(struct intel_ring_buffer *ring)
 {
-	return ring_get_irq(ring, GT_BSD_USER_INTERRUPT);
+	struct drm_device *dev = ring->dev;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+
+	if (!dev->irq_enabled)
+		return false;
+
+	spin_lock(&ring->irq_lock);
+	if (ring->irq_refcount++ == 0) {
+		if (IS_G4X(dev))
+			i915_enable_irq(dev_priv, I915_BSD_USER_INTERRUPT);
+		else
+			ironlake_enable_irq(dev_priv, GT_BSD_USER_INTERRUPT);
+	}
+	spin_unlock(&ring->irq_lock);
+
+	return true;
 }
 static void
 bsd_ring_put_irq(struct intel_ring_buffer *ring)
 {
-	ring_put_irq(ring, GT_BSD_USER_INTERRUPT);
+	struct drm_device *dev = ring->dev;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+
+	spin_lock(&ring->irq_lock);
+	if (--ring->irq_refcount == 0) {
+		if (IS_G4X(dev))
+			i915_disable_irq(dev_priv, I915_BSD_USER_INTERRUPT);
+		else
+			ironlake_disable_irq(dev_priv, GT_BSD_USER_INTERRUPT);
+	}
+	spin_unlock(&ring->irq_lock);
 }
 
 static int