[patch 39/43] drm/i915: dont enable vblanks on disabled pipes
From: Greg KH
Date: Fri Mar 20 2009 - 19:39:48 EST
2.6.28-stable review patch. If anyone has any objections, please let us know.
------------------
From: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
commit 71e0ffa599f54058d9b8724b4b14d0486751681d upstream.
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/gpu/drm/i915/i915_irq.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -400,6 +400,12 @@ int i915_enable_vblank(struct drm_device
{
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))
--
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