1 files changed, 153 insertions, 140 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 82752d6177a4..69b9a42da95e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -33,11 +33,23 @@
 
 #define MAX_NOPID ((u32)~0)
 
-/** These are the interrupts used by the driver */
-#define I915_INTERRUPT_ENABLE_MASK (I915_USER_INTERRUPT |		\
-				    I915_ASLE_INTERRUPT |		\
-				    I915_DISPLAY_PIPE_A_EVENT_INTERRUPT | \
-				    I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)
+/**
+ * Interrupts that are always left unmasked.
+ *
+ * Since pipe events are edge-triggered from the PIPESTAT register to IIR,
+ * we leave them always unmasked in IMR and then control enabling them through
+ * PIPESTAT alone.
+ */
+#define I915_INTERRUPT_ENABLE_FIX (I915_ASLE_INTERRUPT | \
+				   I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |  \
+				   I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)
+
+/** Interrupts that we mask and unmask at runtime. */
+#define I915_INTERRUPT_ENABLE_VAR (I915_USER_INTERRUPT)
+
+/** These are all of the interrupts used by the driver */
+#define I915_INTERRUPT_ENABLE_MASK (I915_INTERRUPT_ENABLE_FIX | \
+				    I915_INTERRUPT_ENABLE_VAR)
 
 void
 i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
@@ -59,6 +71,41 @@ i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
 	}
 }
 
+static inline u32
+i915_pipestat(int pipe)
+{
+	if (pipe == 0)
+		return PIPEASTAT;
+	if (pipe == 1)
+		return PIPEBSTAT;
+	BUG();
+}
+
+void
+i915_enable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
+{
+	if ((dev_priv->pipestat[pipe] & mask) != mask) {
+		u32 reg = i915_pipestat(pipe);
+
+		dev_priv->pipestat[pipe] |= mask;
+		/* Enable the interrupt, clear any pending status */
+		I915_WRITE(reg, dev_priv->pipestat[pipe] | (mask >> 16));
+		(void) I915_READ(reg);
+	}
+}
+
+void
+i915_disable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
+{
+	if ((dev_priv->pipestat[pipe] & mask) != 0) {
+		u32 reg = i915_pipestat(pipe);
+
+		dev_priv->pipestat[pipe] &= ~mask;
+		I915_WRITE(reg, dev_priv->pipestat[pipe]);
+		(void) I915_READ(reg);
+	}
+}
+
 /**
  * i915_pipe_enabled - check if a pipe is enabled
  * @dev: DRM device
@@ -121,80 +168,102 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 iir;
+	u32 iir, new_iir;
 	u32 pipea_stats, pipeb_stats;
+	u32 vblank_status;
+	u32 vblank_enable;
 	int vblank = 0;
+	unsigned long irqflags;
+	int irq_received;
+	int ret = IRQ_NONE;
 
 	atomic_inc(&dev_priv->irq_received);
 
-	if (dev->pdev->msi_enabled)
-		I915_WRITE(IMR, ~0);
 	iir = I915_READ(IIR);
 
-	if (iir == 0) {
-		if (dev->pdev->msi_enabled) {
-			I915_WRITE(IMR, dev_priv->irq_mask_reg);
-			(void) I915_READ(IMR);
-		}
-		return IRQ_NONE;
+	if (IS_I965G(dev)) {
+		vblank_status = I915_START_VBLANK_INTERRUPT_STATUS;
+		vblank_enable = PIPE_START_VBLANK_INTERRUPT_ENABLE;
+	} else {
+		vblank_status = I915_VBLANK_INTERRUPT_STATUS;
+		vblank_enable = I915_VBLANK_INTERRUPT_ENABLE;
 	}
 
-	/*
-	 * Clear the PIPE(A|B)STAT regs before the IIR otherwise
-	 * we may get extra interrupts.
-	 */
-	if (iir & I915_DISPLAY_PIPE_A_EVENT_INTERRUPT) {
+	for (;;) {
+		irq_received = iir != 0;
+
+		/* Can't rely on pipestat interrupt bit in iir as it might
+		 * have been cleared after the pipestat interrupt was received.
+		 * It doesn't set the bit in iir again, but it still produces
+		 * interrupts (for non-MSI).
+		 */
+		spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
 		pipea_stats = I915_READ(PIPEASTAT);
-		if (!(dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A))
-			pipea_stats &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
-					 PIPE_VBLANK_INTERRUPT_ENABLE);
-		else if (pipea_stats & (PIPE_START_VBLANK_INTERRUPT_STATUS|
-					PIPE_VBLANK_INTERRUPT_STATUS)) {
+		pipeb_stats = I915_READ(PIPEBSTAT);
+		/*
+		 * Clear the PIPE(A|B)STAT regs before the IIR
+		 */
+		if (pipea_stats & 0x8000ffff) {
+			I915_WRITE(PIPEASTAT, pipea_stats);
+			irq_received = 1;
+		}
+
+		if (pipeb_stats & 0x8000ffff) {
+			I915_WRITE(PIPEBSTAT, pipeb_stats);
+			irq_received = 1;
+		}
+		spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
+
+		if (!irq_received)
+			break;
+
+		ret = IRQ_HANDLED;
+
+		I915_WRITE(IIR, iir);
+		new_iir = I915_READ(IIR); /* Flush posted writes */
+
+		if (dev_priv->sarea_priv)
+			dev_priv->sarea_priv->last_dispatch =
+				READ_BREADCRUMB(dev_priv);
+
+		if (iir & I915_USER_INTERRUPT) {
+			dev_priv->mm.irq_gem_seqno = i915_get_gem_seqno(dev);
+			DRM_WAKEUP(&dev_priv->irq_queue);
+		}
+
+		if (pipea_stats & vblank_status) {
 			vblank++;
 			drm_handle_vblank(dev, 0);
 		}
 
-		I915_WRITE(PIPEASTAT, pipea_stats);
-	}
-	if (iir & I915_DISPLAY_PIPE_B_EVENT_INTERRUPT) {
-		pipeb_stats = I915_READ(PIPEBSTAT);
-		/* Ack the event */
-		I915_WRITE(PIPEBSTAT, pipeb_stats);
-
-		/* The vblank interrupt gets enabled even if we didn't ask for
-		   it, so make sure it's shut down again */
-		if (!(dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B))
-			pipeb_stats &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
-					 PIPE_VBLANK_INTERRUPT_ENABLE);
-		else if (pipeb_stats & (PIPE_START_VBLANK_INTERRUPT_STATUS|
-					PIPE_VBLANK_INTERRUPT_STATUS)) {
+		if (pipeb_stats & vblank_status) {
 			vblank++;
 			drm_handle_vblank(dev, 1);
 		}
 
-		if (pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS)
+		if ((pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS) ||
+		    (iir & I915_ASLE_INTERRUPT))
 			opregion_asle_intr(dev);
-		I915_WRITE(PIPEBSTAT, pipeb_stats);
-	}
-
-	I915_WRITE(IIR, iir);
-	if (dev->pdev->msi_enabled)
-		I915_WRITE(IMR, dev_priv->irq_mask_reg);
-	(void) I915_READ(IIR); /* Flush posted writes */
-
-	if (dev_priv->sarea_priv)
-		dev_priv->sarea_priv->last_dispatch =
-			READ_BREADCRUMB(dev_priv);
 
-	if (iir & I915_USER_INTERRUPT) {
-		dev_priv->mm.irq_gem_seqno = i915_get_gem_seqno(dev);
-		DRM_WAKEUP(&dev_priv->irq_queue);
+		/* With MSI, interrupts are only generated when iir
+		 * transitions from zero to nonzero.  If another bit got
+		 * set while we were handling the existing iir bits, then
+		 * we would never get another interrupt.
+		 *
+		 * This is fine on non-MSI as well, as if we hit this path
+		 * we avoid exiting the interrupt handler only to generate
+		 * another one.
+		 *
+		 * Note that for MSI this could cause a stray interrupt report
+		 * if an interrupt landed in the time between writing IIR and
+		 * the posting read.  This should be rare enough to never
+		 * trigger the 99% of 100,000 interrupts test for disabling
+		 * stray interrupts.
+		 */
+		iir = new_iir;
 	}
 
-	if (iir & I915_ASLE_INTERRUPT)
-		opregion_asle_intr(dev);
-
-	return IRQ_HANDLED;
+	return ret;
 }
 
 static int i915_emit_irq(struct drm_device * dev)
@@ -330,48 +399,16 @@ int i915_irq_wait(struct drm_device *dev, void *data,
 int i915_enable_vblank(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32	pipestat_reg = 0;
-	u32	pipestat;
-	u32	interrupt = 0;
 	unsigned long irqflags;
 
-	switch (pipe) {
-	case 0:
-		pipestat_reg = PIPEASTAT;
-		interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
-		break;
-	case 1:
-		pipestat_reg = PIPEBSTAT;
-		interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
-		break;
-	default:
-		DRM_ERROR("tried to enable vblank on non-existent pipe %d\n",
-			  pipe);
-		return 0;
-	}
-
 	spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
-	/* Enabling vblank events in IMR comes before PIPESTAT write, or
-	 * there's a race where the PIPESTAT vblank bit gets set to 1, so
-	 * the OR of enabled PIPESTAT bits goes to 1, so the PIPExEVENT in
-	 * ISR flashes to 1, but the IIR bit doesn't get set to 1 because
-	 * IMR masks it.  It doesn't ever get set after we clear the masking
-	 * in IMR because the ISR bit is edge, not level-triggered, on the
-	 * OR of PIPESTAT bits.
-	 */
-	i915_enable_irq(dev_priv, interrupt);
-	pipestat = I915_READ(pipestat_reg);
 	if (IS_I965G(dev))
-		pipestat |= PIPE_START_VBLANK_INTERRUPT_ENABLE;
+		i915_enable_pipestat(dev_priv, pipe,
+				     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_pipestat(dev_priv, pipe,
+				     PIPE_VBLANK_INTERRUPT_ENABLE);
 	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
-
 	return 0;
 }
 
@@ -381,37 +418,12 @@ int i915_enable_vblank(struct drm_device *dev, int pipe)
 void i915_disable_vblank(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32	pipestat_reg = 0;
-	u32	pipestat;
-	u32	interrupt = 0;
 	unsigned long irqflags;
 
-	switch (pipe) {
-	case 0:
-		pipestat_reg = PIPEASTAT;
-		interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
-		break;
-	case 1:
-		pipestat_reg = PIPEBSTAT;
-		interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
-		break;
-	default:
-		DRM_ERROR("tried to disable vblank on non-existent pipe %d\n",
-			  pipe);
-		return;
-		break;
-	}
-
 	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 */
+	i915_disable_pipestat(dev_priv, pipe,
+			      PIPE_VBLANK_INTERRUPT_ENABLE |
+			      PIPE_START_VBLANK_INTERRUPT_ENABLE);
 	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
 }
 
@@ -476,32 +488,35 @@ void i915_driver_irq_preinstall(struct drm_device * dev)
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 
 	I915_WRITE(HWSTAM, 0xeffe);
+	I915_WRITE(PIPEASTAT, 0);
+	I915_WRITE(PIPEBSTAT, 0);
 	I915_WRITE(IMR, 0xffffffff);
 	I915_WRITE(IER, 0x0);
+	(void) I915_READ(IER);
 }
 
 int i915_driver_irq_postinstall(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	int ret, num_pipes = 2;
-
-	/* Set initial unmasked IRQs to just the selected vblank pipes. */
-	dev_priv->irq_mask_reg = ~0;
-
-	ret = drm_vblank_init(dev, num_pipes);
-	if (ret)
-		return ret;
 
 	dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;
-	dev_priv->irq_mask_reg &= ~I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT;
-	dev_priv->irq_mask_reg &= ~I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
 
 	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
 
-	dev_priv->irq_mask_reg &= I915_INTERRUPT_ENABLE_MASK;
+	/* Unmask the interrupts that we always want on. */
+	dev_priv->irq_mask_reg = ~I915_INTERRUPT_ENABLE_FIX;
+
+	dev_priv->pipestat[0] = 0;
+	dev_priv->pipestat[1] = 0;
+
+	/* Disable pipe interrupt enables, clear pending pipe status */
+	I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
+	I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
+	/* Clear pending interrupt status */
+	I915_WRITE(IIR, I915_READ(IIR));
 
-	I915_WRITE(IMR, dev_priv->irq_mask_reg);
 	I915_WRITE(IER, I915_INTERRUPT_ENABLE_MASK);
+	I915_WRITE(IMR, dev_priv->irq_mask_reg);
 	(void) I915_READ(IER);
 
 	opregion_enable_asle(dev);
@@ -513,7 +528,6 @@ int i915_driver_irq_postinstall(struct drm_device *dev)
 void i915_driver_irq_uninstall(struct drm_device * dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
-	u32 temp;
 
 	if (!dev_priv)
 		return;
@@ -521,13 +535,12 @@ void i915_driver_irq_uninstall(struct drm_device * dev)
 	dev_priv->vblank_pipe = 0;
 
 	I915_WRITE(HWSTAM, 0xffffffff);
+	I915_WRITE(PIPEASTAT, 0);
+	I915_WRITE(PIPEBSTAT, 0);
 	I915_WRITE(IMR, 0xffffffff);
 	I915_WRITE(IER, 0x0);
 
-	temp = I915_READ(PIPEASTAT);
-	I915_WRITE(PIPEASTAT, temp);
-	temp = I915_READ(PIPEBSTAT);
-	I915_WRITE(PIPEBSTAT, temp);
-	temp = I915_READ(IIR);
-	I915_WRITE(IIR, temp);
+	I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
+	I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
+	I915_WRITE(IIR, I915_READ(IIR));
 }