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Commit e9d21d7f authored by Keith Packard's avatar Keith Packard Committed by Dave Airlie
Browse files

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: default avatarKeith Packard <keithp@keithp.com>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 4b408939

drivers/gpu/drm/i915/i915_irq.c

+40 −29
Original line number Diff line number Diff line
@@ -481,22 +481,24 @@ static int i915_emit_irq(struct drm_device * dev) 
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)
@@ -584,23 +586,25 @@ int i915_enable_vblank(struct drm_device *dev, int plane) 
	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) {

	spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);

	pipestat = I915_READ(pipestat_reg);

	if (IS_I965G(dev))

		pipestat |= PIPE_START_VBLANK_INTERRUPT_ENABLE;
@@ -610,7 +614,9 @@ int i915_enable_vblank(struct drm_device *dev, int plane) 
	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;

}
@@ -621,23 +627,27 @@ void i915_disable_vblank(struct drm_device *dev, int plane) 
	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) {

	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);
@@ -645,7 +655,8 @@ void i915_disable_vblank(struct drm_device *dev, int plane) 
	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