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-rw-r--r--drivers/gpu/drm/i915/i915_irq.c6
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))