drm/i915: don't enable vblanks on disabled pipes
In some cases userland may be confused and try to wait on vblank events from
pipes that aren't actually enabled. We shouldn't allow this, so return
-EINVAL if the pipe isn't on.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 0cadafb..6290219 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -411,6 +411,12 @@
{
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))