1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 0cadafbef41..6290219de6c 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -411,6 +411,12 @@ int i915_enable_vblank(struct drm_device *dev, int pipe)
 {
         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
         unsigned long irqflags;
+        int pipeconf_reg = (pipe == 0) ? PIPEACONF : PIPEBCONF;
+        u32 pipeconf;
+
+        pipeconf = I915_READ(pipeconf_reg);
+        if (!(pipeconf & PIPEACONF_ENABLE))
+                return -EINVAL;
 
         spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
         if (IS_I965G(dev))