i915: Protect vblank IRQ reg access with spinlock
This uses the same spinlock as the user_irq code as it shares the same
register, ensuring that interrupt registers are updated atomically.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index baae511..671dd79 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -481,22 +481,24 @@
void i915_user_irq_get(struct drm_device *dev)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ unsigned long irqflags;
- spin_lock(&dev_priv->user_irq_lock);
+ spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
if (dev->irq_enabled && (++dev_priv->user_irq_refcount == 1))
i915_enable_irq(dev_priv, I915_USER_INTERRUPT);
- spin_unlock(&dev_priv->user_irq_lock);
+ spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}
void i915_user_irq_put(struct drm_device *dev)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ unsigned long irqflags;
- spin_lock(&dev_priv->user_irq_lock);
+ spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
BUG_ON(dev->irq_enabled && dev_priv->user_irq_refcount <= 0);
if (dev->irq_enabled && (--dev_priv->user_irq_refcount == 0))
i915_disable_irq(dev_priv, I915_USER_INTERRUPT);
- spin_unlock(&dev_priv->user_irq_lock);
+ spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}
static int i915_wait_irq(struct drm_device * dev, int irq_nr)
@@ -584,33 +586,37 @@
int pipe = i915_get_pipe(dev, plane);
u32 pipestat_reg = 0;
u32 pipestat;
+ u32 interrupt = 0;
+ unsigned long irqflags;
switch (pipe) {
case 0:
pipestat_reg = PIPEASTAT;
- i915_enable_irq(dev_priv, I915_DISPLAY_PIPE_A_EVENT_INTERRUPT);
+ interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
break;
case 1:
pipestat_reg = PIPEBSTAT;
- i915_enable_irq(dev_priv, I915_DISPLAY_PIPE_B_EVENT_INTERRUPT);
+ interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
break;
default:
DRM_ERROR("tried to enable vblank on non-existent pipe %d\n",
pipe);
- break;
+ return 0;
}
- if (pipestat_reg) {
- pipestat = I915_READ(pipestat_reg);
- if (IS_I965G(dev))
- pipestat |= PIPE_START_VBLANK_INTERRUPT_ENABLE;
- else
- pipestat |= PIPE_VBLANK_INTERRUPT_ENABLE;
- /* Clear any stale interrupt status */
- pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
- PIPE_VBLANK_INTERRUPT_STATUS);
- I915_WRITE(pipestat_reg, pipestat);
- }
+ spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
+ pipestat = I915_READ(pipestat_reg);
+ if (IS_I965G(dev))
+ pipestat |= PIPE_START_VBLANK_INTERRUPT_ENABLE;
+ else
+ pipestat |= PIPE_VBLANK_INTERRUPT_ENABLE;
+ /* Clear any stale interrupt status */
+ pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
+ PIPE_VBLANK_INTERRUPT_STATUS);
+ I915_WRITE(pipestat_reg, pipestat);
+ (void) I915_READ(pipestat_reg); /* Posting read */
+ i915_enable_irq(dev_priv, interrupt);
+ spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
return 0;
}
@@ -621,31 +627,36 @@
int pipe = i915_get_pipe(dev, plane);
u32 pipestat_reg = 0;
u32 pipestat;
+ u32 interrupt = 0;
+ unsigned long irqflags;
switch (pipe) {
case 0:
pipestat_reg = PIPEASTAT;
- i915_disable_irq(dev_priv, I915_DISPLAY_PIPE_A_EVENT_INTERRUPT);
+ interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
break;
case 1:
pipestat_reg = PIPEBSTAT;
- i915_disable_irq(dev_priv, I915_DISPLAY_PIPE_B_EVENT_INTERRUPT);
+ interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
break;
default:
DRM_ERROR("tried to disable vblank on non-existent pipe %d\n",
pipe);
+ return;
break;
}
- if (pipestat_reg) {
- pipestat = I915_READ(pipestat_reg);
- pipestat &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
- PIPE_VBLANK_INTERRUPT_ENABLE);
- /* Clear any stale interrupt status */
- pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
- PIPE_VBLANK_INTERRUPT_STATUS);
- I915_WRITE(pipestat_reg, pipestat);
- }
+ spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
+ i915_disable_irq(dev_priv, interrupt);
+ pipestat = I915_READ(pipestat_reg);
+ pipestat &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
+ PIPE_VBLANK_INTERRUPT_ENABLE);
+ /* Clear any stale interrupt status */
+ pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
+ PIPE_VBLANK_INTERRUPT_STATUS);
+ I915_WRITE(pipestat_reg, pipestat);
+ (void) I915_READ(pipestat_reg); /* Posting read */
+ spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}
/* Set the vblank monitor pipe