drivers/gpu/drm/i915/i915_irq.c - linux/kernel/git/torvalds/linux - Git at Google

 /* i915_irq.c -- IRQ support for the I915 -*- linux-c -*-
  */
 /*
  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sub license, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial portions
  * of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  */

 #include "drmP.h"
 #include "drm.h"
 #include "i915_drm.h"
 #include "i915_drv.h"
 #include "intel_drv.h"

 #define MAX_NOPID ((u32)~0)

 /**
  * 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)

 #define I915_PIPE_VBLANK_STATUS	(PIPE_START_VBLANK_INTERRUPT_STATUS |\
 				 PIPE_VBLANK_INTERRUPT_STATUS)

 #define I915_PIPE_VBLANK_ENABLE	(PIPE_START_VBLANK_INTERRUPT_ENABLE |\
 				 PIPE_VBLANK_INTERRUPT_ENABLE)

 #define DRM_I915_VBLANK_PIPE_ALL	(DRM_I915_VBLANK_PIPE_A | \
 					 DRM_I915_VBLANK_PIPE_B)

 void
 i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
 {
 	if ((dev_priv->irq_mask_reg & mask) != 0) {
 		dev_priv->irq_mask_reg &= ~mask;
 		I915_WRITE(IMR, dev_priv->irq_mask_reg);
 		(void) I915_READ(IMR);
 	}
 }

 static inline void
 i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
 {
 	if ((dev_priv->irq_mask_reg & mask) != mask) {
 		dev_priv->irq_mask_reg |= mask;
 		I915_WRITE(IMR, dev_priv->irq_mask_reg);
 		(void) I915_READ(IMR);
 	}
 }

 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
  * @pipe: pipe to check
  *
  * Reading certain registers when the pipe is disabled can hang the chip.
  * Use this routine to make sure the PLL is running and the pipe is active
  * before reading such registers if unsure.
  */
 static int
 i915_pipe_enabled(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	unsigned long pipeconf = pipe ? PIPEBCONF : PIPEACONF;

 	if (I915_READ(pipeconf) & PIPEACONF_ENABLE)
 		return 1;

 	return 0;
 }

 /* Called from drm generic code, passed a 'crtc', which
  * we use as a pipe index
  */
 u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	unsigned long high_frame;
 	unsigned long low_frame;
 	u32 high1, high2, low, count;

 	high_frame = pipe ? PIPEBFRAMEHIGH : PIPEAFRAMEHIGH;
 	low_frame = pipe ? PIPEBFRAMEPIXEL : PIPEAFRAMEPIXEL;

 	if (!i915_pipe_enabled(dev, pipe)) {
 		DRM_ERROR("trying to get vblank count for disabled pipe %d\n", pipe);
 		return 0;
 	}

 	/*
 	 * High & low register fields aren't synchronized, so make sure
 	 * we get a low value that's stable across two reads of the high
 	 * register.
 	 */
 	do {
 		high1 = ((I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
 			 PIPE_FRAME_HIGH_SHIFT);
 		low =  ((I915_READ(low_frame) & PIPE_FRAME_LOW_MASK) >>
 			PIPE_FRAME_LOW_SHIFT);
 		high2 = ((I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
 			 PIPE_FRAME_HIGH_SHIFT);
 	} while (high1 != high2);

 	count = (high1 << 8) | low;

 	return count;
 }

 u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	int reg = pipe ? PIPEB_FRMCOUNT_GM45 : PIPEA_FRMCOUNT_GM45;

 	if (!i915_pipe_enabled(dev, pipe)) {
 		DRM_ERROR("trying to get vblank count for disabled pipe %d\n", pipe);
 		return 0;
 	}

 	return I915_READ(reg);
 }

 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;
 	struct drm_i915_master_private *master_priv;
 	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);

 	iir = I915_READ(IIR);

 	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;
 	}

 	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);
 		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->primary->master) {
 			master_priv = dev->primary->master->driver_priv;
 			if (master_priv->sarea_priv)
 				master_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);
 		}

 		if (pipeb_stats & vblank_status) {
 			vblank++;
 			drm_handle_vblank(dev, 1);
 		}

 		if ((pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS) ||
 		    (iir & I915_ASLE_INTERRUPT))
 			opregion_asle_intr(dev);

 		/* 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;
 	}

 	return ret;
 }

 static int i915_emit_irq(struct drm_device * dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
 	RING_LOCALS;

 	i915_kernel_lost_context(dev);

 	DRM_DEBUG("\n");

 	dev_priv->counter++;
 	if (dev_priv->counter > 0x7FFFFFFFUL)
 		dev_priv->counter = 1;
 	if (master_priv->sarea_priv)
 		master_priv->sarea_priv->last_enqueue = dev_priv->counter;

 	BEGIN_LP_RING(4);
 	OUT_RING(MI_STORE_DWORD_INDEX);
 	OUT_RING(I915_BREADCRUMB_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
 	OUT_RING(dev_priv->counter);
 	OUT_RING(MI_USER_INTERRUPT);
 	ADVANCE_LP_RING();

 	return dev_priv->counter;
 }

 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_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_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_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_irqrestore(&dev_priv->user_irq_lock, irqflags);
 }

 static int i915_wait_irq(struct drm_device * dev, int irq_nr)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
 	int ret = 0;

 	DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
 		  READ_BREADCRUMB(dev_priv));

 	if (READ_BREADCRUMB(dev_priv) >= irq_nr) {
 		if (master_priv->sarea_priv)
 			master_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
 		return 0;
 	}

 	if (master_priv->sarea_priv)
 		master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;

 	i915_user_irq_get(dev);
 	DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
 		    READ_BREADCRUMB(dev_priv) >= irq_nr);
 	i915_user_irq_put(dev);

 	if (ret == -EBUSY) {
 		DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
 			  READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
 	}

 	return ret;
 }

 /* Needs the lock as it touches the ring.
  */
 int i915_irq_emit(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	drm_i915_irq_emit_t *emit = data;
 	int result;

 	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return -EINVAL;
 	}

 	RING_LOCK_TEST_WITH_RETURN(dev, file_priv);

 	mutex_lock(&dev->struct_mutex);
 	result = i915_emit_irq(dev);
 	mutex_unlock(&dev->struct_mutex);

 	if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
 		DRM_ERROR("copy_to_user\n");
 		return -EFAULT;
 	}

 	return 0;
 }

 /* Doesn't need the hardware lock.
  */
 int i915_irq_wait(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	drm_i915_irq_wait_t *irqwait = data;

 	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return -EINVAL;
 	}

 	return i915_wait_irq(dev, irqwait->irq_seq);
 }

 /* Called from drm generic code, passed 'crtc' which
  * we use as a pipe index
  */
 int i915_enable_vblank(struct drm_device *dev, int pipe)
 {
 	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))
 		i915_enable_pipestat(dev_priv, pipe,
 				     PIPE_START_VBLANK_INTERRUPT_ENABLE);
 	else
 		i915_enable_pipestat(dev_priv, pipe,
 				     PIPE_VBLANK_INTERRUPT_ENABLE);
 	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
 	return 0;
 }

 /* Called from drm generic code, passed 'crtc' which
  * we use as a pipe index
  */
 void i915_disable_vblank(struct drm_device *dev, int pipe)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	unsigned long irqflags;

 	spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
 	i915_disable_pipestat(dev_priv, pipe,
 			      PIPE_VBLANK_INTERRUPT_ENABLE |
 			      PIPE_START_VBLANK_INTERRUPT_ENABLE);
 	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
 }

 void i915_enable_interrupt (struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	opregion_enable_asle(dev);
 	dev_priv->irq_enabled = 1;
 }


 /* Set the vblank monitor pipe
  */
 int i915_vblank_pipe_set(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;

 	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return -EINVAL;
 	}

 	return 0;
 }

 int i915_vblank_pipe_get(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	drm_i915_vblank_pipe_t *pipe = data;

 	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return -EINVAL;
 	}

 	pipe->pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;

 	return 0;
 }

 /**
  * Schedule buffer swap at given vertical blank.
  */
 int i915_vblank_swap(struct drm_device *dev, void *data,
 		     struct drm_file *file_priv)
 {
 	/* The delayed swap mechanism was fundamentally racy, and has been
 	 * removed.  The model was that the client requested a delayed flip/swap
 	 * from the kernel, then waited for vblank before continuing to perform
 	 * rendering.  The problem was that the kernel might wake the client
 	 * up before it dispatched the vblank swap (since the lock has to be
 	 * held while touching the ringbuffer), in which case the client would
 	 * clear and start the next frame before the swap occurred, and
 	 * flicker would occur in addition to likely missing the vblank.
 	 *
 	 * In the absence of this ioctl, userland falls back to a correct path
 	 * of waiting for a vblank, then dispatching the swap on its own.
 	 * Context switching to userland and back is plenty fast enough for
 	 * meeting the requirements of vblank swapping.
 	 */
 	return -EINVAL;
 }

 /* drm_dma.h hooks
 */
 void i915_driver_irq_preinstall(struct drm_device * dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

 	atomic_set(&dev_priv->irq_received, 0);

 	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;

 	dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;

 	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */

 	/* 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(IER, I915_INTERRUPT_ENABLE_MASK);
 	I915_WRITE(IMR, dev_priv->irq_mask_reg);
 	(void) I915_READ(IER);

 	opregion_enable_asle(dev);
 	DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);

 	return 0;
 }

 void i915_driver_irq_uninstall(struct drm_device * dev)
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

 	if (!dev_priv)
 		return;

 	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);

 	I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
 	I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
 	I915_WRITE(IIR, I915_READ(IIR));
 }
	/* i915_irq.c -- IRQ support for the I915 -- linux-c --
	*/
	/*
	* Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sub license, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial portions
	* of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
	* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
	* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
	* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
	* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*
	*/

	#include "drmP.h"
	#include "drm.h"
	#include "i915_drm.h"
	#include "i915_drv.h"
	#include "intel_drv.h"

	#define MAX_NOPID ((u32)~0)

	/**
	* 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)

	#define I915_PIPE_VBLANK_STATUS (PIPE_START_VBLANK_INTERRUPT_STATUS \|\
	PIPE_VBLANK_INTERRUPT_STATUS)

	#define I915_PIPE_VBLANK_ENABLE (PIPE_START_VBLANK_INTERRUPT_ENABLE \|\
	PIPE_VBLANK_INTERRUPT_ENABLE)

	#define DRM_I915_VBLANK_PIPE_ALL (DRM_I915_VBLANK_PIPE_A \| \
	DRM_I915_VBLANK_PIPE_B)

	void
	i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
	{
	if ((dev_priv->irq_mask_reg & mask) != 0) {
	dev_priv->irq_mask_reg &= ~mask;
	I915_WRITE(IMR, dev_priv->irq_mask_reg);
	(void) I915_READ(IMR);
	}
	}

	static inline void
	i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
	{
	if ((dev_priv->irq_mask_reg & mask) != mask) {
	dev_priv->irq_mask_reg \|= mask;
	I915_WRITE(IMR, dev_priv->irq_mask_reg);
	(void) I915_READ(IMR);
	}
	}

	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
	* @pipe: pipe to check
	*
	* Reading certain registers when the pipe is disabled can hang the chip.
	* Use this routine to make sure the PLL is running and the pipe is active
	* before reading such registers if unsure.
	*/
	static int
	i915_pipe_enabled(struct drm_device *dev, int pipe)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;
	unsigned long pipeconf = pipe ? PIPEBCONF : PIPEACONF;

	if (I915_READ(pipeconf) & PIPEACONF_ENABLE)
	return 1;

	return 0;
	}

	/* Called from drm generic code, passed a 'crtc', which
	* we use as a pipe index
	*/
	u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;
	unsigned long high_frame;
	unsigned long low_frame;
	u32 high1, high2, low, count;

	high_frame = pipe ? PIPEBFRAMEHIGH : PIPEAFRAMEHIGH;
	low_frame = pipe ? PIPEBFRAMEPIXEL : PIPEAFRAMEPIXEL;

	if (!i915_pipe_enabled(dev, pipe)) {
	DRM_ERROR("trying to get vblank count for disabled pipe %d\n", pipe);
	return 0;
	}

	/*
	* High & low register fields aren't synchronized, so make sure
	* we get a low value that's stable across two reads of the high
	* register.
	*/
	do {
	high1 = ((I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
	PIPE_FRAME_HIGH_SHIFT);
	low = ((I915_READ(low_frame) & PIPE_FRAME_LOW_MASK) >>
	PIPE_FRAME_LOW_SHIFT);
	high2 = ((I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
	PIPE_FRAME_HIGH_SHIFT);
	} while (high1 != high2);

	count = (high1 << 8) \| low;

	return count;
	}

	u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;
	int reg = pipe ? PIPEB_FRMCOUNT_GM45 : PIPEA_FRMCOUNT_GM45;

	if (!i915_pipe_enabled(dev, pipe)) {
	DRM_ERROR("trying to get vblank count for disabled pipe %d\n", pipe);
	return 0;
	}

	return I915_READ(reg);
	}

	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;
	struct drm_i915_master_private *master_priv;
	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);

	iir = I915_READ(IIR);

	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;
	}

	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);
	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->primary->master) {
	master_priv = dev->primary->master->driver_priv;
	if (master_priv->sarea_priv)
	master_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);
	}

	if (pipeb_stats & vblank_status) {
	vblank++;
	drm_handle_vblank(dev, 1);
	}

	if ((pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS) \|\|
	(iir & I915_ASLE_INTERRUPT))
	opregion_asle_intr(dev);

	/* 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;
	}

	return ret;
	}

	static int i915_emit_irq(struct drm_device * dev)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;
	struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
	RING_LOCALS;

	i915_kernel_lost_context(dev);

	DRM_DEBUG("\n");

	dev_priv->counter++;
	if (dev_priv->counter > 0x7FFFFFFFUL)
	dev_priv->counter = 1;
	if (master_priv->sarea_priv)
	master_priv->sarea_priv->last_enqueue = dev_priv->counter;

	BEGIN_LP_RING(4);
	OUT_RING(MI_STORE_DWORD_INDEX);
	OUT_RING(I915_BREADCRUMB_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
	OUT_RING(dev_priv->counter);
	OUT_RING(MI_USER_INTERRUPT);
	ADVANCE_LP_RING();

	return dev_priv->counter;
	}

	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_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_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_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_irqrestore(&dev_priv->user_irq_lock, irqflags);
	}

	static int i915_wait_irq(struct drm_device * dev, int irq_nr)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;
	struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
	int ret = 0;

	DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
	READ_BREADCRUMB(dev_priv));

	if (READ_BREADCRUMB(dev_priv) >= irq_nr) {
	if (master_priv->sarea_priv)
	master_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
	return 0;
	}

	if (master_priv->sarea_priv)
	master_priv->sarea_priv->perf_boxes \|= I915_BOX_WAIT;

	i915_user_irq_get(dev);
	DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
	READ_BREADCRUMB(dev_priv) >= irq_nr);
	i915_user_irq_put(dev);

	if (ret == -EBUSY) {
	DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
	READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
	}

	return ret;
	}

	/* Needs the lock as it touches the ring.
	*/
	int i915_irq_emit(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;
	drm_i915_irq_emit_t *emit = data;
	int result;

	if (!dev_priv) {
	DRM_ERROR("called with no initialization\n");
	return -EINVAL;
	}

	RING_LOCK_TEST_WITH_RETURN(dev, file_priv);

	mutex_lock(&dev->struct_mutex);
	result = i915_emit_irq(dev);
	mutex_unlock(&dev->struct_mutex);

	if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
	DRM_ERROR("copy_to_user\n");
	return -EFAULT;
	}

	return 0;
	}

	/* Doesn't need the hardware lock.
	*/
	int i915_irq_wait(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;
	drm_i915_irq_wait_t *irqwait = data;

	if (!dev_priv) {
	DRM_ERROR("called with no initialization\n");
	return -EINVAL;
	}

	return i915_wait_irq(dev, irqwait->irq_seq);
	}

	/* Called from drm generic code, passed 'crtc' which
	* we use as a pipe index
	*/
	int i915_enable_vblank(struct drm_device *dev, int pipe)
	{
	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))
	i915_enable_pipestat(dev_priv, pipe,
	PIPE_START_VBLANK_INTERRUPT_ENABLE);
	else
	i915_enable_pipestat(dev_priv, pipe,
	PIPE_VBLANK_INTERRUPT_ENABLE);
	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
	return 0;
	}

	/* Called from drm generic code, passed 'crtc' which
	* we use as a pipe index
	*/
	void i915_disable_vblank(struct drm_device *dev, int pipe)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;
	unsigned long irqflags;

	spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
	i915_disable_pipestat(dev_priv, pipe,
	PIPE_VBLANK_INTERRUPT_ENABLE \|
	PIPE_START_VBLANK_INTERRUPT_ENABLE);
	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
	}

	void i915_enable_interrupt (struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	opregion_enable_asle(dev);
	dev_priv->irq_enabled = 1;
	}


	/* Set the vblank monitor pipe
	*/
	int i915_vblank_pipe_set(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;

	if (!dev_priv) {
	DRM_ERROR("called with no initialization\n");
	return -EINVAL;
	}

	return 0;
	}

	int i915_vblank_pipe_get(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;
	drm_i915_vblank_pipe_t *pipe = data;

	if (!dev_priv) {
	DRM_ERROR("called with no initialization\n");
	return -EINVAL;
	}

	pipe->pipe = DRM_I915_VBLANK_PIPE_A \| DRM_I915_VBLANK_PIPE_B;

	return 0;
	}

	/**
	* Schedule buffer swap at given vertical blank.
	*/
	int i915_vblank_swap(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	/* The delayed swap mechanism was fundamentally racy, and has been
	* removed. The model was that the client requested a delayed flip/swap
	* from the kernel, then waited for vblank before continuing to perform
	* rendering. The problem was that the kernel might wake the client
	* up before it dispatched the vblank swap (since the lock has to be
	* held while touching the ringbuffer), in which case the client would
	* clear and start the next frame before the swap occurred, and
	* flicker would occur in addition to likely missing the vblank.
	*
	* In the absence of this ioctl, userland falls back to a correct path
	* of waiting for a vblank, then dispatching the swap on its own.
	* Context switching to userland and back is plenty fast enough for
	* meeting the requirements of vblank swapping.
	*/
	return -EINVAL;
	}

	/* drm_dma.h hooks
	*/
	void i915_driver_irq_preinstall(struct drm_device * dev)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;

	atomic_set(&dev_priv->irq_received, 0);

	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;

	dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A \| DRM_I915_VBLANK_PIPE_B;

	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */

	/* 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(IER, I915_INTERRUPT_ENABLE_MASK);
	I915_WRITE(IMR, dev_priv->irq_mask_reg);
	(void) I915_READ(IER);

	opregion_enable_asle(dev);
	DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);

	return 0;
	}

	void i915_driver_irq_uninstall(struct drm_device * dev)
	{
	drm_i915_private_t dev_priv = (drm_i915_private_t ) dev->dev_private;

	if (!dev_priv)
	return;

	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);

	I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
	I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
	I915_WRITE(IIR, I915_READ(IIR));
	}