drm/libdrm/intel/intel_bufmgr_fake.c

/**************************************************************************
 * 
 * Copyright 2006 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.
 * 
 **************************************************************************/

/* Originally a fake version of the buffer manager so that we can
 * prototype the changes in a driver fairly quickly, has been fleshed
 * out to a fully functional interim solution.
 *
 * Basically wraps the old style memory management in the new
 * programming interface, but is more expressive and avoids many of
 * the bugs in the old texture manager.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <xf86drm.h>
#include <pthread.h>
#include "intel_bufmgr.h"
#include "intel_bufmgr_priv.h"
#include "drm.h"
#include "i915_drm.h"
#include "mm.h"
#include "libdrm_lists.h"

#define ALIGN(value, alignment)  ((value + alignment - 1) & ~(alignment - 1))

#define DBG(...) do {					\
   if (bufmgr_fake->bufmgr.debug)			\
      drmMsg(__VA_ARGS__);				\
} while (0)

/* Internal flags:
 */
#define BM_NO_BACKING_STORE			0x00000001
#define BM_NO_FENCE_SUBDATA			0x00000002
#define BM_PINNED				0x00000004

/* Wrapper around mm.c's mem_block, which understands that you must
 * wait for fences to expire before memory can be freed.  This is
 * specific to our use of memcpy for uploads - an upload that was
 * processed through the command queue wouldn't need to care about
 * fences.
 */
#define MAX_RELOCS 4096

struct fake_buffer_reloc
{
   /** Buffer object that the relocation points at. */
   dri_bo *target_buf;
   /** Offset of the relocation entry within reloc_buf. */
   uint32_t offset;
   /** Cached value of the offset when we last performed this relocation. */
   uint32_t last_target_offset;
   /** Value added to target_buf's offset to get the relocation entry. */
   uint32_t delta;
   /** Cache domains the target buffer is read into. */
   uint32_t read_domains;
   /** Cache domain the target buffer will have dirty cachelines in. */
   uint32_t write_domain;
};

struct block {
   struct block *next, *prev;
   struct mem_block *mem;	/* BM_MEM_AGP */

   /**
    * Marks that the block is currently in the aperture and has yet to be
    * fenced.
    */
   unsigned on_hardware:1;
   /**
    * Marks that the block is currently fenced (being used by rendering) and
    * can't be freed until @fence is passed.
    */
   unsigned fenced:1;

   /** Fence cookie for the block. */
   unsigned fence; /* Split to read_fence, write_fence */

   dri_bo *bo;
   void *virtual;
};

typedef struct _bufmgr_fake {
   dri_bufmgr bufmgr;

   pthread_mutex_t lock;

   unsigned long low_offset;
   unsigned long size;
   void *virtual;

   struct mem_block *heap;

   unsigned buf_nr;		/* for generating ids */

   /**
    * List of blocks which are currently in the GART but haven't been
    * fenced yet.
    */
   struct block on_hardware;
   /**
    * List of blocks which are in the GART and have an active fence on them.
    */
   struct block fenced;
   /**
    * List of blocks which have an expired fence and are ready to be evicted.
    */
   struct block lru;

   unsigned int last_fence;

   unsigned fail:1;
   unsigned need_fence:1;
   int thrashing;

   /**
    * Driver callback to emit a fence, returning the cookie.
    *
    * This allows the driver to hook in a replacement for the DRM usage in
    * bufmgr_fake.
    *
    * Currently, this also requires that a write flush be emitted before
    * emitting the fence, but this should change.
    */
   unsigned int (*fence_emit)(void *private);
   /** Driver callback to wait for a fence cookie to have passed. */
   void (*fence_wait)(unsigned int fence, void *private);
   void *fence_priv;

   /**
    * Driver callback to execute a buffer.
    *
    * This allows the driver to hook in a replacement for the DRM usage in
    * bufmgr_fake.
    */
   int (*exec)(dri_bo *bo, unsigned int used, void *priv);
   void *exec_priv;

   /** Driver-supplied argument to driver callbacks */
   void *driver_priv;
   /* Pointer to kernel-updated sarea data for the last completed user irq */
   volatile int *last_dispatch;

   int fd;

   int debug;

   int performed_rendering;
} dri_bufmgr_fake;

typedef struct _dri_bo_fake {
   dri_bo bo;

   unsigned id;			/* debug only */
   const char *name;

   unsigned dirty:1;
   /** has the card written to this buffer - we make need to copy it back */
   unsigned card_dirty:1;
   unsigned int refcount;
   /* Flags may consist of any of the DRM_BO flags, plus
    * DRM_BO_NO_BACKING_STORE and BM_NO_FENCE_SUBDATA, which are the first two
    * driver private flags.
    */
   uint64_t flags;
   /** Cache domains the target buffer is read into. */
   uint32_t read_domains;
   /** Cache domain the target buffer will have dirty cachelines in. */
   uint32_t write_domain;

   unsigned int alignment;
   int is_static, validated;
   unsigned int map_count;

   /** relocation list */
   struct fake_buffer_reloc *relocs;
   int nr_relocs;
   /**
    * Total size of the target_bos of this buffer.
    *
    * Used for estimation in check_aperture.
    */
   unsigned int child_size;

   struct block *block;
   void *backing_store;
   void (*invalidate_cb)(dri_bo *bo, void *ptr);
   void *invalidate_ptr;
} dri_bo_fake;

static int clear_fenced(dri_bufmgr_fake *bufmgr_fake,
			unsigned int fence_cookie);

#define MAXFENCE 0x7fffffff

static int FENCE_LTE( unsigned a, unsigned b )
{
   if (a == b)
      return 1;

   if (a < b && b - a < (1<<24))
      return 1;

   if (a > b && MAXFENCE - a + b < (1<<24))
      return 1;

   return 0;
}

void intel_bufmgr_fake_set_fence_callback(dri_bufmgr *bufmgr,
					  unsigned int (*emit)(void *priv),
					  void (*wait)(unsigned int fence,
						       void *priv),
					  void *priv)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   bufmgr_fake->fence_emit = emit;
   bufmgr_fake->fence_wait = wait;
   bufmgr_fake->fence_priv = priv;
}

static unsigned int
_fence_emit_internal(dri_bufmgr_fake *bufmgr_fake)
{
   struct drm_i915_irq_emit ie;
   int ret, seq = 1;

   if (bufmgr_fake->fence_emit != NULL) {
      seq = bufmgr_fake->fence_emit(bufmgr_fake->fence_priv);
      return seq;
   }

   ie.irq_seq = &seq;
   ret = drmCommandWriteRead(bufmgr_fake->fd, DRM_I915_IRQ_EMIT,
			     &ie, sizeof(ie));
   if (ret) {
      drmMsg("%s: drm_i915_irq_emit: %d\n", __FUNCTION__, ret);
      abort();
   }

   DBG("emit 0x%08x\n", seq);
   return seq;
}

static void
_fence_wait_internal(dri_bufmgr_fake *bufmgr_fake, int seq)
{
   struct drm_i915_irq_wait iw;
   int hw_seq, busy_count = 0;
   int ret;
   int kernel_lied;

   if (bufmgr_fake->fence_wait != NULL) {
      bufmgr_fake->fence_wait(seq, bufmgr_fake->fence_priv);
      clear_fenced(bufmgr_fake, seq);
      return;
   }

   DBG("wait 0x%08x\n", iw.irq_seq);

   iw.irq_seq = seq;

   /* The kernel IRQ_WAIT implementation is all sorts of broken.
    * 1) It returns 1 to 0x7fffffff instead of using the full 32-bit unsigned
    *    range.
    * 2) It returns 0 if hw_seq >= seq, not seq - hw_seq < 0 on the 32-bit
    *    signed range.
    * 3) It waits if seq < hw_seq, not seq - hw_seq > 0 on the 32-bit
    *    signed range.
    * 4) It returns -EBUSY in 3 seconds even if the hardware is still
    *    successfully chewing through buffers.
    *
    * Assume that in userland we treat sequence numbers as ints, which makes
    * some of the comparisons convenient, since the sequence numbers are
    * all postive signed integers.
    *
    * From this we get several cases we need to handle.  Here's a timeline.
    * 0x2   0x7                                         0x7ffffff8   0x7ffffffd
    *   |    |                                                   |    |
    * -------------------------------------------------------------------
    *
    * A) Normal wait for hw to catch up
    * hw_seq seq
    *   |    |
    * -------------------------------------------------------------------
    * seq - hw_seq = 5.  If we call IRQ_WAIT, it will wait for hw to catch up.
    *
    * B) Normal wait for a sequence number that's already passed.
    * seq    hw_seq
    *   |    |
    * -------------------------------------------------------------------
    * seq - hw_seq = -5.  If we call IRQ_WAIT, it returns 0 quickly.
    *
    * C) Hardware has already wrapped around ahead of us
    * hw_seq                                                         seq
    *   |                                                             |
    * -------------------------------------------------------------------
    * seq - hw_seq = 0x80000000 - 5.  If we called IRQ_WAIT, it would wait
    * for hw_seq >= seq, which may never occur.  Thus, we want to catch this
    * in userland and return 0.
    *
    * D) We've wrapped around ahead of the hardware.
    * seq                                                           hw_seq
    *   |                                                             |
    * -------------------------------------------------------------------
    * seq - hw_seq = -(0x80000000 - 5).  If we called IRQ_WAIT, it would return
    * 0 quickly because hw_seq >= seq, even though the hardware isn't caught up.
    * Thus, we need to catch this early return in userland and bother the
    * kernel until the hardware really does catch up.
    *
    * E) Hardware might wrap after we test in userland.
    *                                                         hw_seq  seq
    *                                                            |    |
    * -------------------------------------------------------------------
    * seq - hw_seq = 5.  If we call IRQ_WAIT, it will likely see seq >= hw_seq
    * and wait.  However, suppose hw_seq wraps before we make it into the
    * kernel.  The kernel sees hw_seq >= seq and waits for 3 seconds then
    * returns -EBUSY.  This is case C).  We should catch this and then return
    * successfully.
    *
    * F) Hardware might take a long time on a buffer.
    * hw_seq seq
    *   |    |
    * -------------------------------------------------------------------
    * seq - hw_seq = 5.  If we call IRQ_WAIT, if sequence 2 through 5 take too
    * long, it will return -EBUSY.  Batchbuffers in the gltestperf demo were
    * seen to take up to 7 seconds.  We should catch early -EBUSY return
    * and keep trying.
    */

   do {
      /* Keep a copy of last_dispatch so that if the wait -EBUSYs because the
       * hardware didn't catch up in 3 seconds, we can see if it at least made
       * progress and retry.
       */
      hw_seq = *bufmgr_fake->last_dispatch;

      /* Catch case C */
      if (seq - hw_seq > 0x40000000)
	 return;

      ret = drmCommandWrite(bufmgr_fake->fd, DRM_I915_IRQ_WAIT,
			    &iw, sizeof(iw));
      /* Catch case D */
      kernel_lied = (ret == 0) && (seq - *bufmgr_fake->last_dispatch <
				   -0x40000000);

      /* Catch case E */
      if (ret == -EBUSY && (seq - *bufmgr_fake->last_dispatch > 0x40000000))
	 ret = 0;

      /* Catch case F: Allow up to 15 seconds chewing on one buffer. */
      if ((ret == -EBUSY) && (hw_seq != *bufmgr_fake->last_dispatch))
	 busy_count = 0;
      else
	 busy_count++;
   } while (kernel_lied || ret == -EAGAIN || ret == -EINTR ||
	    (ret == -EBUSY && busy_count < 5));

   if (ret != 0) {
      drmMsg("%s:%d: Error waiting for fence: %s.\n", __FILE__, __LINE__,
	     strerror(-ret));
      abort();
   }
   clear_fenced(bufmgr_fake, seq);
}

static int
_fence_test(dri_bufmgr_fake *bufmgr_fake, unsigned fence)
{
   /* Slight problem with wrap-around:
    */
   return fence == 0 || FENCE_LTE(fence, bufmgr_fake->last_fence);
}

/**
 * Allocate a memory manager block for the buffer.
 */
static int
alloc_block(dri_bo *bo)
{
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   dri_bufmgr_fake *bufmgr_fake= (dri_bufmgr_fake *)bo->bufmgr;
   struct block *block = (struct block *)calloc(sizeof *block, 1);
   unsigned int align_log2 = ffs(bo_fake->alignment) - 1;
   unsigned int sz;

   if (!block)
      return 1;

   sz = (bo->size + bo_fake->alignment - 1) & ~(bo_fake->alignment - 1);

   block->mem = mmAllocMem(bufmgr_fake->heap, sz, align_log2, 0);
   if (!block->mem) {
      free(block);
      return 0;
   }

   DRMINITLISTHEAD(block);

   /* Insert at head or at tail???   
    */
   DRMLISTADDTAIL(block, &bufmgr_fake->lru);

   block->virtual = (uint8_t *)bufmgr_fake->virtual +
      block->mem->ofs - bufmgr_fake->low_offset;
   block->bo = bo;

   bo_fake->block = block;

   return 1;
}

/* Release the card storage associated with buf:
 */
static void free_block(dri_bufmgr_fake *bufmgr_fake, struct block *block)
{
   dri_bo_fake *bo_fake;
   DBG("free block %p %08x %d %d\n", block, block->mem->ofs, block->on_hardware, block->fenced);

   if (!block)
      return;

   bo_fake = (dri_bo_fake *)block->bo;
   if (!(bo_fake->flags & (BM_PINNED | BM_NO_BACKING_STORE)) && (bo_fake->card_dirty == 1)) {
     memcpy(bo_fake->backing_store, block->virtual, block->bo->size);
     bo_fake->card_dirty = 0;
     bo_fake->dirty = 1;
   }

   if (block->on_hardware) {
      block->bo = NULL;
   }
   else if (block->fenced) {
      block->bo = NULL;
   }
   else {
      DBG("    - free immediately\n");
      DRMLISTDEL(block);

      mmFreeMem(block->mem);
      free(block);
   }
}

static void
alloc_backing_store(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   assert(!bo_fake->backing_store);
   assert(!(bo_fake->flags & (BM_PINNED|BM_NO_BACKING_STORE)));

   bo_fake->backing_store = malloc(bo->size);

   DBG("alloc_backing - buf %d %p %d\n", bo_fake->id, bo_fake->backing_store, bo->size);
   assert(bo_fake->backing_store);
}

static void
free_backing_store(dri_bo *bo)
{
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   if (bo_fake->backing_store) {
      assert(!(bo_fake->flags & (BM_PINNED|BM_NO_BACKING_STORE)));
      free(bo_fake->backing_store);
      bo_fake->backing_store = NULL;
   }
}

static void
set_dirty(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   if (bo_fake->flags & BM_NO_BACKING_STORE && bo_fake->invalidate_cb != NULL)
      bo_fake->invalidate_cb(bo, bo_fake->invalidate_ptr);

   assert(!(bo_fake->flags & BM_PINNED));

   DBG("set_dirty - buf %d\n", bo_fake->id);
   bo_fake->dirty = 1;
}

static int
evict_lru(dri_bufmgr_fake *bufmgr_fake, unsigned int max_fence)
{
   struct block *block, *tmp;

   DBG("%s\n", __FUNCTION__);

   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->lru) {
      dri_bo_fake *bo_fake = (dri_bo_fake *)block->bo;

      if (bo_fake != NULL && (bo_fake->flags & BM_NO_FENCE_SUBDATA))
	 continue;

      if (block->fence && max_fence && !FENCE_LTE(block->fence, max_fence))
	 return 0;

      set_dirty(&bo_fake->bo);
      bo_fake->block = NULL;

      free_block(bufmgr_fake, block);
      return 1;
   }

   return 0;
}

static int
evict_mru(dri_bufmgr_fake *bufmgr_fake)
{
   struct block *block, *tmp;

   DBG("%s\n", __FUNCTION__);

   DRMLISTFOREACHSAFEREVERSE(block, tmp, &bufmgr_fake->lru) {
      dri_bo_fake *bo_fake = (dri_bo_fake *)block->bo;

      if (bo_fake && (bo_fake->flags & BM_NO_FENCE_SUBDATA))
	 continue;

      set_dirty(&bo_fake->bo);
      bo_fake->block = NULL;

      free_block(bufmgr_fake, block);
      return 1;
   }

   return 0;
}

/**
 * Removes all objects from the fenced list older than the given fence.
 */
static int clear_fenced(dri_bufmgr_fake *bufmgr_fake,
			unsigned int fence_cookie)
{
   struct block *block, *tmp;
   int ret = 0;

   bufmgr_fake->last_fence = fence_cookie;
   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->fenced) {
      assert(block->fenced);

      if (_fence_test(bufmgr_fake, block->fence)) {

	 block->fenced = 0;

	 if (!block->bo) {
	    DBG("delayed free: offset %x sz %x\n",
		block->mem->ofs, block->mem->size);
	    DRMLISTDEL(block);
	    mmFreeMem(block->mem);
	    free(block);
	 }
	 else {
	    DBG("return to lru: offset %x sz %x\n",
		block->mem->ofs, block->mem->size);
	    DRMLISTDEL(block);
	    DRMLISTADDTAIL(block, &bufmgr_fake->lru);
	 }

	 ret = 1;
      }
      else {
	 /* Blocks are ordered by fence, so if one fails, all from
	  * here will fail also:
	  */
	DBG("fence not passed: offset %x sz %x %d %d \n",
	    block->mem->ofs, block->mem->size, block->fence, bufmgr_fake->last_fence);
	 break;
      }
   }

   DBG("%s: %d\n", __FUNCTION__, ret);
   return ret;
}

static void fence_blocks(dri_bufmgr_fake *bufmgr_fake, unsigned fence)
{
   struct block *block, *tmp;

   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->on_hardware) {
      DBG("Fence block %p (sz 0x%x ofs %x buf %p) with fence %d\n", block,
	  block->mem->size, block->mem->ofs, block->bo, fence);
      block->fence = fence;

      block->on_hardware = 0;
      block->fenced = 1;

      /* Move to tail of pending list here
       */
      DRMLISTDEL(block);
      DRMLISTADDTAIL(block, &bufmgr_fake->fenced);
   }

   assert(DRMLISTEMPTY(&bufmgr_fake->on_hardware));
}

static int evict_and_alloc_block(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   assert(bo_fake->block == NULL);

   /* Search for already free memory:
    */
   if (alloc_block(bo))
      return 1;

   /* If we're not thrashing, allow lru eviction to dig deeper into
    * recently used textures.  We'll probably be thrashing soon:
    */
   if (!bufmgr_fake->thrashing) {
      while (evict_lru(bufmgr_fake, 0))
	 if (alloc_block(bo))
	    return 1;
   }

   /* Keep thrashing counter alive?
    */
   if (bufmgr_fake->thrashing)
      bufmgr_fake->thrashing = 20;

   /* Wait on any already pending fences - here we are waiting for any
    * freed memory that has been submitted to hardware and fenced to
    * become available:
    */
   while (!DRMLISTEMPTY(&bufmgr_fake->fenced)) {
      uint32_t fence = bufmgr_fake->fenced.next->fence;
      _fence_wait_internal(bufmgr_fake, fence);

      if (alloc_block(bo))
	 return 1;
   }

   if (!DRMLISTEMPTY(&bufmgr_fake->on_hardware)) {
      while (!DRMLISTEMPTY(&bufmgr_fake->fenced)) {
	 uint32_t fence = bufmgr_fake->fenced.next->fence;
	 _fence_wait_internal(bufmgr_fake, fence);
      }

      if (!bufmgr_fake->thrashing) {
	 DBG("thrashing\n");
      }
      bufmgr_fake->thrashing = 20;

      if (alloc_block(bo))
	 return 1;
   }

   while (evict_mru(bufmgr_fake))
      if (alloc_block(bo))
	 return 1;

   DBG("%s 0x%x bytes failed\n", __FUNCTION__, bo->size);

   return 0;
}

/***********************************************************************
 * Public functions
 */

/**
 * Wait for hardware idle by emitting a fence and waiting for it.
 */
static void
dri_bufmgr_fake_wait_idle(dri_bufmgr_fake *bufmgr_fake)
{
   unsigned int cookie;

   cookie = _fence_emit_internal(bufmgr_fake);
   _fence_wait_internal(bufmgr_fake, cookie);
}

/**
 * Wait for rendering to a buffer to complete.
 *
 * It is assumed that the bathcbuffer which performed the rendering included
 * the necessary flushing.
 */
static void
dri_fake_bo_wait_rendering_locked(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   if (bo_fake->block == NULL || !bo_fake->block->fenced)
      return;

   _fence_wait_internal(bufmgr_fake, bo_fake->block->fence);
}

static void
dri_fake_bo_wait_rendering(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;

   pthread_mutex_lock(&bufmgr_fake->lock);
   dri_fake_bo_wait_rendering_locked(bo);
   pthread_mutex_unlock(&bufmgr_fake->lock);
}

/* Specifically ignore texture memory sharing.
 *  -- just evict everything
 *  -- and wait for idle
 */
void
intel_bufmgr_fake_contended_lock_take(dri_bufmgr *bufmgr)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;
   struct block *block, *tmp;

   pthread_mutex_lock(&bufmgr_fake->lock);

   bufmgr_fake->need_fence = 1;
   bufmgr_fake->fail = 0;

   /* Wait for hardware idle.  We don't know where acceleration has been
    * happening, so we'll need to wait anyway before letting anything get
    * put on the card again.
    */
   dri_bufmgr_fake_wait_idle(bufmgr_fake);

   /* Check that we hadn't released the lock without having fenced the last
    * set of buffers.
    */
   assert(DRMLISTEMPTY(&bufmgr_fake->fenced));
   assert(DRMLISTEMPTY(&bufmgr_fake->on_hardware));

   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->lru) {
      assert(_fence_test(bufmgr_fake, block->fence));
      set_dirty(block->bo);
   }

   pthread_mutex_unlock(&bufmgr_fake->lock);
}

static dri_bo *
dri_fake_bo_alloc(dri_bufmgr *bufmgr, const char *name,
		  unsigned long size, unsigned int alignment)
{
   dri_bufmgr_fake *bufmgr_fake;
   dri_bo_fake *bo_fake;

   bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   assert(size != 0);

   bo_fake = calloc(1, sizeof(*bo_fake));
   if (!bo_fake)
      return NULL;

   bo_fake->bo.size = size;
   bo_fake->bo.offset = -1;
   bo_fake->bo.virtual = NULL;
   bo_fake->bo.bufmgr = bufmgr;
   bo_fake->refcount = 1;

   /* Alignment must be a power of two */
   assert((alignment & (alignment - 1)) == 0);
   if (alignment == 0)
      alignment = 1;
   bo_fake->alignment = alignment;
   bo_fake->id = ++bufmgr_fake->buf_nr;
   bo_fake->name = name;
   bo_fake->flags = 0;
   bo_fake->is_static = 0;

   DBG("drm_bo_alloc: (buf %d: %s, %d kb)\n", bo_fake->id, bo_fake->name,
       bo_fake->bo.size / 1024);

   return &bo_fake->bo;
}

dri_bo *
intel_bo_fake_alloc_static(dri_bufmgr *bufmgr, const char *name,
			   unsigned long offset, unsigned long size,
			   void *virtual)
{
   dri_bufmgr_fake *bufmgr_fake;
   dri_bo_fake *bo_fake;

   bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   assert(size != 0);

   bo_fake = calloc(1, sizeof(*bo_fake));
   if (!bo_fake)
      return NULL;

   bo_fake->bo.size = size;
   bo_fake->bo.offset = offset;
   bo_fake->bo.virtual = virtual;
   bo_fake->bo.bufmgr = bufmgr;
   bo_fake->refcount = 1;
   bo_fake->id = ++bufmgr_fake->buf_nr;
   bo_fake->name = name;
   bo_fake->flags = BM_PINNED | DRM_BO_FLAG_NO_MOVE;
   bo_fake->is_static = 1;

   DBG("drm_bo_alloc_static: (buf %d: %s, %d kb)\n", bo_fake->id, bo_fake->name,
       bo_fake->bo.size / 1024);

   return &bo_fake->bo;
}

static void
dri_fake_bo_reference(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   pthread_mutex_lock(&bufmgr_fake->lock);
   bo_fake->refcount++;
   pthread_mutex_unlock(&bufmgr_fake->lock);
}

static void
dri_fake_bo_reference_locked(dri_bo *bo)
{
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   bo_fake->refcount++;
}

static void
dri_fake_bo_unreference_locked(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   int i;

   if (--bo_fake->refcount == 0) {
      assert(bo_fake->map_count == 0);
      /* No remaining references, so free it */
      if (bo_fake->block)
	 free_block(bufmgr_fake, bo_fake->block);
      free_backing_store(bo);

      for (i = 0; i < bo_fake->nr_relocs; i++)
	 dri_fake_bo_unreference_locked(bo_fake->relocs[i].target_buf);

      DBG("drm_bo_unreference: free buf %d %s\n", bo_fake->id, bo_fake->name);

      free(bo_fake->relocs);
      free(bo);
   }
}

static void
dri_fake_bo_unreference(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;

   pthread_mutex_lock(&bufmgr_fake->lock);
   dri_fake_bo_unreference_locked(bo);
   pthread_mutex_unlock(&bufmgr_fake->lock);
}

/**
 * Set the buffer as not requiring backing store, and instead get the callback
 * invoked whenever it would be set dirty.
 */
void intel_bo_fake_disable_backing_store(dri_bo *bo,
					 void (*invalidate_cb)(dri_bo *bo,
							       void *ptr),
					 void *ptr)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   pthread_mutex_lock(&bufmgr_fake->lock);

   if (bo_fake->backing_store)
      free_backing_store(bo);

   bo_fake->flags |= BM_NO_BACKING_STORE;

   DBG("disable_backing_store set buf %d dirty\n", bo_fake->id);
   bo_fake->dirty = 1;
   bo_fake->invalidate_cb = invalidate_cb;
   bo_fake->invalidate_ptr = ptr;

   /* Note that it is invalid right from the start.  Also note
    * invalidate_cb is called with the bufmgr locked, so cannot
    * itself make bufmgr calls.
    */
   if (invalidate_cb != NULL)
      invalidate_cb(bo, ptr);

   pthread_mutex_unlock(&bufmgr_fake->lock);
}

/**
 * Map a buffer into bo->virtual, allocating either card memory space (If
 * BM_NO_BACKING_STORE or BM_PINNED) or backing store, as necessary.
 */
static int
dri_fake_bo_map_locked(dri_bo *bo, int write_enable)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   /* Static buffers are always mapped. */
   if (bo_fake->is_static) {
      if (bo_fake->card_dirty) {
         dri_bufmgr_fake_wait_idle(bufmgr_fake);
         bo_fake->card_dirty = 0;
      }
      return 0;
   }

   /* Allow recursive mapping.  Mesa may recursively map buffers with
    * nested display loops, and it is used internally in bufmgr_fake
    * for relocation.
    */
   if (bo_fake->map_count++ != 0)
      return 0;

   {
      DBG("drm_bo_map: (buf %d: %s, %d kb)\n", bo_fake->id, bo_fake->name,
	  bo_fake->bo.size / 1024);

      if (bo->virtual != NULL) {
	 drmMsg("%s: already mapped\n", __FUNCTION__);
	 abort();
      }
      else if (bo_fake->flags & (BM_NO_BACKING_STORE|BM_PINNED)) {

	 if (!bo_fake->block && !evict_and_alloc_block(bo)) {
	    DBG("%s: alloc failed\n", __FUNCTION__);
	    bufmgr_fake->fail = 1;
	    return 1;
	 }
	 else {
	    assert(bo_fake->block);
	    bo_fake->dirty = 0;

	    if (!(bo_fake->flags & BM_NO_FENCE_SUBDATA) &&
		bo_fake->block->fenced) {
	       dri_fake_bo_wait_rendering_locked(bo);
	    }

	    bo->virtual = bo_fake->block->virtual;
	 }
      }
      else {
	 if (write_enable)
	    set_dirty(bo);

	 if (bo_fake->backing_store == 0)
	    alloc_backing_store(bo);

         if ((bo_fake->card_dirty == 1) && bo_fake->block) {
            if (bo_fake->block->fenced)
               dri_fake_bo_wait_rendering_locked(bo);

            memcpy(bo_fake->backing_store, bo_fake->block->virtual, bo_fake->block->bo->size);
            bo_fake->card_dirty = 0;
         }

	 bo->virtual = bo_fake->backing_store;
      }
   }

   return 0;
}

static int
dri_fake_bo_map(dri_bo *bo, int write_enable)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   int ret;

   pthread_mutex_lock(&bufmgr_fake->lock);
   ret = dri_fake_bo_map_locked(bo, write_enable);
   pthread_mutex_unlock(&bufmgr_fake->lock);

   return ret;
}

static int
dri_fake_bo_unmap_locked(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   /* Static buffers are always mapped. */
   if (bo_fake->is_static)
      return 0;

   assert(bo_fake->map_count != 0);
   if (--bo_fake->map_count != 0)
      return 0;

   DBG("drm_bo_unmap: (buf %d: %s, %d kb)\n", bo_fake->id, bo_fake->name,
       bo_fake->bo.size / 1024);

   bo->virtual = NULL;

   return 0;
}

static int
dri_fake_bo_unmap(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   int ret;

   pthread_mutex_lock(&bufmgr_fake->lock);
   ret = dri_fake_bo_unmap_locked(bo);
   pthread_mutex_unlock(&bufmgr_fake->lock);

   return ret;
}

static void
dri_fake_kick_all_locked(dri_bufmgr_fake *bufmgr_fake)
{
   struct block *block, *tmp;

   bufmgr_fake->performed_rendering = 0;
   /* okay for ever BO that is on the HW kick it off.
      seriously not afraid of the POLICE right now */
   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->on_hardware) {
      dri_bo_fake *bo_fake = (dri_bo_fake *)block->bo;

      block->on_hardware = 0;
      free_block(bufmgr_fake, block);
      bo_fake->block = NULL;
      bo_fake->validated = 0;
      if (!(bo_fake->flags & BM_NO_BACKING_STORE))
         bo_fake->dirty = 1;
   }

}

static int
dri_fake_bo_validate(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;

   bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;

   DBG("drm_bo_validate: (buf %d: %s, %d kb)\n", bo_fake->id, bo_fake->name,
       bo_fake->bo.size / 1024);

   /* Sanity check: Buffers should be unmapped before being validated.
    * This is not so much of a problem for bufmgr_fake, but TTM refuses,
    * and the problem is harder to debug there.
    */
   assert(bo_fake->map_count == 0);

   if (bo_fake->is_static) {
      /* Add it to the needs-fence list */
      bufmgr_fake->need_fence = 1;
      return 0;
   }

   /* Allocate the card memory */
   if (!bo_fake->block && !evict_and_alloc_block(bo)) {
      bufmgr_fake->fail = 1;
      DBG("Failed to validate buf %d:%s\n", bo_fake->id, bo_fake->name);
      return -1;
   }

   assert(bo_fake->block);
   assert(bo_fake->block->bo == &bo_fake->bo);

   bo->offset = bo_fake->block->mem->ofs;

   /* Upload the buffer contents if necessary */
   if (bo_fake->dirty) {
      DBG("Upload dirty buf %d:%s, sz %d offset 0x%x\n", bo_fake->id,
	  bo_fake->name, bo->size, bo_fake->block->mem->ofs);

      assert(!(bo_fake->flags &
	       (BM_NO_BACKING_STORE|BM_PINNED)));

      /* Actually, should be able to just wait for a fence on the memory,
       * which we would be tracking when we free it.  Waiting for idle is
       * a sufficiently large hammer for now.
       */
      dri_bufmgr_fake_wait_idle(bufmgr_fake);

      /* we may never have mapped this BO so it might not have any backing
       * store if this happens it should be rare, but 0 the card memory
       * in any case */
      if (bo_fake->backing_store)
         memcpy(bo_fake->block->virtual, bo_fake->backing_store, bo->size);
      else
         memset(bo_fake->block->virtual, 0, bo->size);

      bo_fake->dirty = 0;
   }

   bo_fake->block->fenced = 0;
   bo_fake->block->on_hardware = 1;
   DRMLISTDEL(bo_fake->block);
   DRMLISTADDTAIL(bo_fake->block, &bufmgr_fake->on_hardware);

   bo_fake->validated = 1;
   bufmgr_fake->need_fence = 1;

   return 0;
}

static void
dri_fake_fence_validated(dri_bufmgr *bufmgr)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;
   unsigned int cookie;

   cookie = _fence_emit_internal(bufmgr_fake);
   fence_blocks(bufmgr_fake, cookie);

   DBG("drm_fence_validated: 0x%08x cookie\n", cookie);
}

static void
dri_fake_destroy(dri_bufmgr *bufmgr)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   pthread_mutex_destroy(&bufmgr_fake->lock);
   mmDestroy(bufmgr_fake->heap);
   free(bufmgr);
}

static int
dri_fake_emit_reloc(dri_bo *reloc_buf,
		    uint32_t read_domains, uint32_t write_domain,
		    uint32_t delta, uint32_t offset, dri_bo *target_buf)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)reloc_buf->bufmgr;
   struct fake_buffer_reloc *r;
   dri_bo_fake *reloc_fake = (dri_bo_fake *)reloc_buf;
   dri_bo_fake *target_fake = (dri_bo_fake *)target_buf;
   int i;

   pthread_mutex_lock(&bufmgr_fake->lock);

   assert(reloc_buf);
   assert(target_buf);

   if (reloc_fake->relocs == NULL) {
      reloc_fake->relocs = malloc(sizeof(struct fake_buffer_reloc) *
				  MAX_RELOCS);
   }

   r = &reloc_fake->relocs[reloc_fake->nr_relocs++];

   assert(reloc_fake->nr_relocs <= MAX_RELOCS);

   dri_fake_bo_reference_locked(target_buf);

   if (!target_fake->is_static) {
      reloc_fake->child_size += ALIGN(target_buf->size, target_fake->alignment);
      reloc_fake->child_size += target_fake->child_size;
   }
   r->target_buf = target_buf;
   r->offset = offset;
   r->last_target_offset = target_buf->offset;
   r->delta = delta;
   r->read_domains = read_domains;
   r->write_domain = write_domain;

   if (bufmgr_fake->debug) {
      /* Check that a conflicting relocation hasn't already been emitted. */
      for (i = 0; i < reloc_fake->nr_relocs - 1; i++) {
	 struct fake_buffer_reloc *r2 = &reloc_fake->relocs[i];

	 assert(r->offset != r2->offset);
      }
   }

   pthread_mutex_unlock(&bufmgr_fake->lock);

   return 0;
}

/**
 * Incorporates the validation flags associated with each relocation into
 * the combined validation flags for the buffer on this batchbuffer submission.
 */
static void
dri_fake_calculate_domains(dri_bo *bo)
{
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   int i;

   for (i = 0; i < bo_fake->nr_relocs; i++) {
      struct fake_buffer_reloc *r = &bo_fake->relocs[i];
      dri_bo_fake *target_fake = (dri_bo_fake *)r->target_buf;

      /* Do the same for the tree of buffers we depend on */
      dri_fake_calculate_domains(r->target_buf);

      target_fake->read_domains |= r->read_domains;
      target_fake->write_domain |= r->write_domain;
   }
}


static int
dri_fake_reloc_and_validate_buffer(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   int i, ret;

   assert(bo_fake->map_count == 0);

   for (i = 0; i < bo_fake->nr_relocs; i++) {
      struct fake_buffer_reloc *r = &bo_fake->relocs[i];
      dri_bo_fake *target_fake = (dri_bo_fake *)r->target_buf;
      uint32_t reloc_data;

      /* Validate the target buffer if that hasn't been done. */
      if (!target_fake->validated) {
         ret = dri_fake_reloc_and_validate_buffer(r->target_buf);
         if (ret != 0) {
            if (bo->virtual != NULL)
                dri_fake_bo_unmap_locked(bo);
            return ret;
         }
      }

      /* Calculate the value of the relocation entry. */
      if (r->target_buf->offset != r->last_target_offset) {
	 reloc_data = r->target_buf->offset + r->delta;

	 if (bo->virtual == NULL)
	    dri_fake_bo_map_locked(bo, 1);

	 *(uint32_t *)((uint8_t *)bo->virtual + r->offset) = reloc_data;

	 r->last_target_offset = r->target_buf->offset;
      }
   }

   if (bo->virtual != NULL)
      dri_fake_bo_unmap_locked(bo);

   if (bo_fake->write_domain != 0) {
      if (!(bo_fake->flags & (BM_NO_BACKING_STORE|BM_PINNED))) {
         if (bo_fake->backing_store == 0)
            alloc_backing_store(bo);
      }
      bo_fake->card_dirty = 1;
      bufmgr_fake->performed_rendering = 1;
   }

   return dri_fake_bo_validate(bo);
}

static void
dri_bo_fake_post_submit(dri_bo *bo)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *bo_fake = (dri_bo_fake *)bo;
   int i;

   for (i = 0; i < bo_fake->nr_relocs; i++) {
      struct fake_buffer_reloc *r = &bo_fake->relocs[i];
      dri_bo_fake *target_fake = (dri_bo_fake *)r->target_buf;

      if (target_fake->validated)
	 dri_bo_fake_post_submit(r->target_buf);

      DBG("%s@0x%08x + 0x%08x -> %s@0x%08x + 0x%08x\n",
	  bo_fake->name, (uint32_t)bo->offset, r->offset,
	  target_fake->name, (uint32_t)r->target_buf->offset, r->delta);
   }

   assert(bo_fake->map_count == 0);
   bo_fake->validated = 0;
   bo_fake->read_domains = 0;
   bo_fake->write_domain = 0;
}


void intel_bufmgr_fake_set_exec_callback(dri_bufmgr *bufmgr,
					 int (*exec)(dri_bo *bo,
						     unsigned int used,
						     void *priv),
					 void *priv)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   bufmgr_fake->exec = exec;
   bufmgr_fake->exec_priv = priv;
}

static int
dri_fake_bo_exec(dri_bo *bo, int used,
		 drm_clip_rect_t *cliprects, int num_cliprects,
		 int DR4)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo->bufmgr;
   dri_bo_fake *batch_fake = (dri_bo_fake *)bo;
   struct drm_i915_batchbuffer batch;
   int ret;
   int retry_count = 0;

   pthread_mutex_lock(&bufmgr_fake->lock);

   bufmgr_fake->performed_rendering = 0;

   dri_fake_calculate_domains(bo);

   batch_fake->read_domains = I915_GEM_DOMAIN_COMMAND;

   /* we've ran out of RAM so blow the whole lot away and retry */
 restart:
   ret = dri_fake_reloc_and_validate_buffer(bo);
   if (bufmgr_fake->fail == 1) {
      if (retry_count == 0) {
         retry_count++;
         dri_fake_kick_all_locked(bufmgr_fake);
         bufmgr_fake->fail = 0;
         goto restart;
      } else /* dump out the memory here */
         mmDumpMemInfo(bufmgr_fake->heap);
   }

   assert(ret == 0);

   if (bufmgr_fake->exec != NULL) {
      int ret = bufmgr_fake->exec(bo, used, bufmgr_fake->exec_priv);
      if (ret != 0) {
	 pthread_mutex_unlock(&bufmgr_fake->lock);
	 return ret;
      }
   } else {
      batch.start = bo->offset;
      batch.used = used;
      batch.cliprects = cliprects;
      batch.num_cliprects = num_cliprects;
      batch.DR1 = 0;
      batch.DR4 = DR4;

      if (drmCommandWrite(bufmgr_fake->fd, DRM_I915_BATCHBUFFER, &batch,
			  sizeof(batch))) {
	 drmMsg("DRM_I915_BATCHBUFFER: %d\n", -errno);
	 pthread_mutex_unlock(&bufmgr_fake->lock);
	 return -errno;
      }
   }

   dri_fake_fence_validated(bo->bufmgr);

   dri_bo_fake_post_submit(bo);

   pthread_mutex_unlock(&bufmgr_fake->lock);

   return 0;
}

/**
 * Return an error if the list of BOs will exceed the aperture size.
 *
 * This is a rough guess and likely to fail, as during the validate sequence we
 * may place a buffer in an inopportune spot early on and then fail to fit
 * a set smaller than the aperture.
 */
static int
dri_fake_check_aperture_space(dri_bo **bo_array, int count)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bo_array[0]->bufmgr;
   unsigned int sz = 0;
   int i;

   for (i = 0; i < count; i++) {
      dri_bo_fake *bo_fake = (dri_bo_fake *)bo_array[i];

      if (bo_fake == NULL)
	 continue;

      if (!bo_fake->is_static)
	 sz += ALIGN(bo_array[i]->size, bo_fake->alignment);
      sz += bo_fake->child_size;
   }

   if (sz > bufmgr_fake->size) {
      DBG("check_space: overflowed bufmgr size, %dkb vs %dkb\n",
	  sz / 1024, bufmgr_fake->size / 1024);
      return -1;
   }

   DBG("drm_check_space: sz %dkb vs bufgr %dkb\n", sz / 1024 ,
       bufmgr_fake->size / 1024);
   return 0;
}

/**
 * Evicts all buffers, waiting for fences to pass and copying contents out
 * as necessary.
 *
 * Used by the X Server on LeaveVT, when the card memory is no longer our
 * own.
 */
void
intel_bufmgr_fake_evict_all(dri_bufmgr *bufmgr)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;
   struct block *block, *tmp;

   pthread_mutex_lock(&bufmgr_fake->lock);

   bufmgr_fake->need_fence = 1;
   bufmgr_fake->fail = 0;

   /* Wait for hardware idle.  We don't know where acceleration has been
    * happening, so we'll need to wait anyway before letting anything get
    * put on the card again.
    */
   dri_bufmgr_fake_wait_idle(bufmgr_fake);

   /* Check that we hadn't released the lock without having fenced the last
    * set of buffers.
    */
   assert(DRMLISTEMPTY(&bufmgr_fake->fenced));
   assert(DRMLISTEMPTY(&bufmgr_fake->on_hardware));

   DRMLISTFOREACHSAFE(block, tmp, &bufmgr_fake->lru) {
      /* Releases the memory, and memcpys dirty contents out if necessary. */
      free_block(bufmgr_fake, block);
   }

   pthread_mutex_unlock(&bufmgr_fake->lock);
}
void intel_bufmgr_fake_set_last_dispatch(dri_bufmgr *bufmgr,
					 volatile unsigned int *last_dispatch)
{
   dri_bufmgr_fake *bufmgr_fake = (dri_bufmgr_fake *)bufmgr;

   bufmgr_fake->last_dispatch = (volatile int *)last_dispatch;
}

dri_bufmgr *
intel_bufmgr_fake_init(int fd,
		       unsigned long low_offset, void *low_virtual,
		       unsigned long size,
		       volatile unsigned int *last_dispatch)
{
   dri_bufmgr_fake *bufmgr_fake;

   bufmgr_fake = calloc(1, sizeof(*bufmgr_fake));

   if (pthread_mutex_init(&bufmgr_fake->lock, NULL) != 0) {
      free(bufmgr_fake);
      return NULL;
   }

   /* Initialize allocator */
   DRMINITLISTHEAD(&bufmgr_fake->fenced);
   DRMINITLISTHEAD(&bufmgr_fake->on_hardware);
   DRMINITLISTHEAD(&bufmgr_fake->lru);

   bufmgr_fake->low_offset = low_offset;
   bufmgr_fake->virtual = low_virtual;
   bufmgr_fake->size = size;
   bufmgr_fake->heap = mmInit(low_offset, size);

   /* Hook in methods */
   bufmgr_fake->bufmgr.bo_alloc = dri_fake_bo_alloc;
   bufmgr_fake->bufmgr.bo_reference = dri_fake_bo_reference;
   bufmgr_fake->bufmgr.bo_unreference = dri_fake_bo_unreference;
   bufmgr_fake->bufmgr.bo_map = dri_fake_bo_map;
   bufmgr_fake->bufmgr.bo_unmap = dri_fake_bo_unmap;
   bufmgr_fake->bufmgr.bo_wait_rendering = dri_fake_bo_wait_rendering;
   bufmgr_fake->bufmgr.bo_emit_reloc = dri_fake_emit_reloc;
   bufmgr_fake->bufmgr.destroy = dri_fake_destroy;
   bufmgr_fake->bufmgr.bo_exec = dri_fake_bo_exec;
   bufmgr_fake->bufmgr.check_aperture_space = dri_fake_check_aperture_space;
   bufmgr_fake->bufmgr.debug = 0;

   bufmgr_fake->fd = fd;
   bufmgr_fake->last_dispatch = (volatile int *)last_dispatch;

   return &bufmgr_fake->bufmgr;
}