shared-core/i915_dma.c


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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS 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.
 *
 * Authors:
 *    Gareth Hughes <gareth@valinux.com>
 */

#include <linux/config.h>
#include "radeon.h"
#include "drmP.h"
#include "drm.h"
#include "radeon_drm.h"
#include "radeon_drv.h"
#include "ati_pcigart.h"

#include "drm_agpsupport.h"
#include "drm_auth.h"
#include "drm_bufs.h"
#include "drm_context.h"
#include "drm_dma.h"
#include "drm_drawable.h"
#include "drm_drv.h"
#include "drm_fops.h"
#include "drm_init.h"
#include "drm_ioctl.h"
#include "drm_lock.h"
#include "drm_memory.h"
#include "drm_proc.h"
#include "drm_vm.h"
#include "drm_stub.h"
#include "drm_scatter.h"
/* i915_dma.c -- DMA support for the I915 -*- linux-c -*-
 */
/**************************************************************************
 * 
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 * 
 **************************************************************************/

#define __NO_VERSION__
#include "i915.h"
#include "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"


static void i915_print_status_page(drm_device_t *dev)
{
      	drm_i915_private_t *dev_priv = dev->dev_private;
	u32 *temp = dev_priv->hw_status_page;

	if (!temp) {
		DRM_DEBUG("no status page\n");
		return;
	}

   	DRM_DEBUG(  "hw_status: Interrupt Status : %x\n", temp[0]);
   	DRM_DEBUG(  "hw_status: LpRing Head ptr : %x\n", temp[1]);
   	DRM_DEBUG(  "hw_status: IRing Head ptr : %x\n", temp[2]);
      	DRM_DEBUG(  "hw_status: Reserved : %x\n", temp[3]);
   	DRM_DEBUG(  "hw_status: Driver Counter : %d\n", temp[5]);

}


/* Really want an OS-independent resettable timer.  Would like to have
 * this loop run for (eg) 3 sec, but have the timer reset every time
 * the head pointer changes, so that EBUSY only happens if the ring
 * actually stalls for (eg) 3 seconds.
 */
int i915_wait_ring( drm_device_t *dev, int n, const char *caller )
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
   	drm_i915_ring_buffer_t *ring = &(dev_priv->ring);
	u32 last_head = I915_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
	int i;

	for ( i = 0 ; i < 10000 ; i++ ) {
		ring->head = I915_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
	   	ring->space = ring->head - (ring->tail+8);
		if (ring->space < 0) ring->space += ring->Size;
		if ( ring->space >= n )
			return 0;
		
		dev_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;

		if (ring->head != last_head) 
			i = 0;

		last_head = ring->head;
	}

	return DRM_ERR(EBUSY);
}

void i915_kernel_lost_context(drm_device_t *dev)
{
      	drm_i915_private_t *dev_priv = dev->dev_private;
   	drm_i915_ring_buffer_t *ring = &(dev_priv->ring);
      
   	ring->head = I915_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
     	ring->tail = I915_READ(LP_RING + RING_TAIL) & TAIL_ADDR;
     	ring->space = ring->head - (ring->tail+8);
     	if (ring->space < 0) ring->space += ring->Size;

	if (ring->head == ring->tail)
		dev_priv->sarea_priv->perf_boxes |= I915_BOX_RING_EMPTY;
}


int i915_cleanup(drm_device_t *dev)
{
	/* Make sure interrupts are disabled here because the uninstall ioctl
	 * may not have been called from userspace and after dev_private
	 * is freed, it's too late.
	 */
	if (dev->irq) DRM(irq_uninstall)(dev);

	if (dev->dev_private) {
	   	drm_i915_private_t *dev_priv = 
	     		(drm_i915_private_t *) dev->dev_private;
	   
	   	if (dev_priv->ring.virtual_start) {
		   	DRM_IOREMAPFREE( &dev_priv->ring.map, dev);
		}

	   	if (dev_priv->hw_status_page) {
			pci_free_consistent(dev->pdev, PAGE_SIZE,
				      dev_priv->hw_status_page,
				      dev_priv->dma_status_page);
		   	/* Need to rewrite hardware status page */
		   	I915_WRITE(0x02080, 0x1ffff000);
		}

	   	DRM(free)(dev->dev_private, sizeof(drm_i915_private_t), 
			 DRM_MEM_DRIVER);

	   	dev->dev_private = NULL;
	}

   	return 0;
}


static int i915_initialize(drm_device_t *dev, 
			       drm_i915_private_t *dev_priv,
			       drm_i915_init_t *init)
{
   	memset(dev_priv, 0, sizeof(drm_i915_private_t));

	DRM_GETSAREA();
	if(!dev_priv->sarea) {
		DRM_ERROR("can not find sarea!\n");
		dev->dev_private = (void *)dev_priv;
		i915_cleanup(dev);
		return DRM_ERR(EINVAL);
	}

	DRM_FIND_MAP( dev_priv->mmio_map, init->mmio_offset );
	if(!dev_priv->mmio_map) {
		dev->dev_private = (void *)dev_priv;
		i915_cleanup(dev);
		DRM_ERROR("can not find mmio map!\n");
		return DRM_ERR(EINVAL);
	}

	dev_priv->sarea_priv = (drm_i915_sarea_t *)
		((u8 *)dev_priv->sarea->handle +
		 init->sarea_priv_offset);

   	dev_priv->ring.Start = init->ring_start;
   	dev_priv->ring.End = init->ring_end;
   	dev_priv->ring.Size = init->ring_size;
   	dev_priv->ring.tail_mask = dev_priv->ring.Size - 1;
		
	dev_priv->ring.map.offset = init->ring_start;
	dev_priv->ring.map.size = init->ring_size;
	dev_priv->ring.map.type = 0;
	dev_priv->ring.map.flags = 0;
	dev_priv->ring.map.mtrr = 0;

	DRM_IOREMAP( &dev_priv->ring.map, dev );

   	if (dev_priv->ring.map.handle == NULL) {
		dev->dev_private = (void *) dev_priv;
	   	i915_cleanup(dev);
	   	DRM_ERROR("can not ioremap virtual address for"
			  " ring buffer\n");
	   	return DRM_ERR(ENOMEM);
	}

   	dev_priv->ring.virtual_start = dev_priv->ring.map.handle;
   
	dev_priv->back_offset = init->back_offset;
	dev_priv->front_offset = init->front_offset;
	dev_priv->current_page = 0;
	dev_priv->sarea_priv->pf_current_page = dev_priv->current_page;

	/* We are using separate values as placeholders for mechanisms for
	 * private backbuffer/depthbuffer usage.
	 */
	dev_priv->use_mi_batchbuffer_start = 0;

	/* Allow hardware batchbuffers unless told otherwise.
	 */
	dev_priv->allow_batchbuffer = 1;

   	/* Program Hardware Status Page */
   	dev_priv->hw_status_page =
		pci_alloc_consistent( dev->pdev, PAGE_SIZE, 
						&dev_priv->dma_status_page );

   	if (!dev_priv->hw_status_page) {
		dev->dev_private = (void *)dev_priv;
		i915_cleanup(dev);
		DRM_ERROR("Can not allocate hardware status page\n");
		return DRM_ERR(ENOMEM);
	}
   	memset(dev_priv->hw_status_page, 0, PAGE_SIZE);
	DRM_DEBUG("hw status page @ %p\n", dev_priv->hw_status_page);
   
   	I915_WRITE(0x02080, dev_priv->dma_status_page);
	DRM_DEBUG("Enabled hardware status page\n");
   
	dev->dev_private = (void *)dev_priv;

   	return 0;
}


static int i915_resume(drm_device_t *dev)
{
	drm_i915_private_t *dev_priv = 
		(drm_i915_private_t *) dev->dev_private;

	DRM_DEBUG( "%s\n", __FUNCTION__);
		   
	if(!dev_priv->sarea) {
		DRM_ERROR("can not find sarea!\n");
		return DRM_ERR(EINVAL);
	}

	if(!dev_priv->mmio_map) {
		DRM_ERROR("can not find mmio map!\n");
		return DRM_ERR(EINVAL);
	}

   	if (dev_priv->ring.map.handle == NULL) {
	   	DRM_ERROR("can not ioremap virtual address for"
			  " ring buffer\n");
	   	return DRM_ERR(ENOMEM);
	}

   	/* Program Hardware Status Page */
   	if (!dev_priv->hw_status_page) {
		DRM_ERROR("Can not find hardware status page\n");
		return DRM_ERR(EINVAL);
	}
	DRM_DEBUG("hw status page @ %p\n", dev_priv->hw_status_page);
   
   	I915_WRITE(0x02080, dev_priv->dma_status_page);
	DRM_DEBUG("Enabled hardware status page\n");

   	return 0;
}


int i915_dma_init( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;
   	drm_i915_private_t *dev_priv;
   	drm_i915_init_t init;
   	int retcode = 0;
	
  	DRM_COPY_FROM_USER_IOCTL( init, (drm_i915_init_t *)data, sizeof(init));
	
   	switch(init.func) {
	 	case I915_INIT_DMA:
			dev_priv = DRM(alloc)(sizeof(drm_i915_private_t), 
					      DRM_MEM_DRIVER);
	   		if(dev_priv == NULL) 
				return DRM_ERR(ENOMEM);
	   		retcode = i915_initialize(dev, dev_priv, &init);
	   	break;
	 	case I915_CLEANUP_DMA:
	   		retcode = i915_cleanup(dev);
	   	break;
		case I915_RESUME_DMA:
			retcode = i915_resume(dev);
	   	break;
	 	default:
	   		retcode = -EINVAL;
	   	break;
	}
   
   	return retcode;
}


/* Implement basically the same security restrictions as hardware does
 * for MI_BATCH_NON_SECURE.  These can be made stricter at any time.
 *
 * Most of the calculations below involve calculating the size of a
 * particular instruction.  It's important to get the size right as
 * that tells us where the next instruction to check is.  Any illegal
 * instruction detected will be given a size of zero, which is a
 * signal to abort the rest of the buffer.
 */
static int do_validate_cmd( int cmd )
{
	switch (((cmd>>29) & 0x7)) {
	case 0x0:
		switch ((cmd>>23) & 0x3f) {
		case 0x0: 
			return 1; /* MI_NOOP */
		case 0x4: 
			return 1; /* MI_FLUSH */
		default: 
			return 0; /* disallow everything else */
		}
		break;
	case 0x1: 
		return 0;	/* reserved */
	case 0x2: 
		return (cmd & 0xff) + 2; /* 2d commands */
	case 0x3:
		if (((cmd>>24) & 0x1f) <= 0x18)
			return 1;

		switch ((cmd>>24) & 0x1f) {
		case 0x1c: 
			return 1;
		case 0x1d:
			return (cmd & 0xffff) + 2;
		case 0x1e: 
			if (cmd & (1<<23)) 
				return (cmd & 0xffff) + 1;
			else
				return 1;
		case 0x1f:
			if ((cmd & (1<<23)) == 0) /* inline vertices */
				return (cmd & 0x1ffff) + 2;
			else if (cmd & (1<<17)) /* indirect random */
				if ((cmd & 0xffff) == 0)
					return 0; /* unknown length, too hard */
				else
					return (((cmd & 0xffff) + 1) / 2) + 1;
			else
				return 2; /* indirect sequential */
		default: 
			return 0;
		}
	default:
		return 0;
	}

	return 0;
}

static int validate_cmd( int cmd )
{
	int ret = do_validate_cmd( cmd );
	
/* 	printk("validate_cmd( %x ): %d\n", cmd, ret); */

	return ret;
}
	
	
static int i915_emit_cmds( drm_device_t *dev,
			   int *buffer,
			   int dwords )
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
	int i;
	RING_LOCALS;

	for (i = 0 ; i < dwords ; ) {
		int cmd, sz;

		if (DRM_COPY_FROM_USER_UNCHECKED(&cmd, &buffer[i], sizeof(cmd)))
			return DRM_ERR( EINVAL );

/* 		printk("%d/%d ", i, dwords); */

		if ((sz = validate_cmd(cmd)) == 0 || i + sz > dwords) 
			return DRM_ERR( EINVAL );

		BEGIN_LP_RING( sz );
		OUT_RING(cmd);

		while (++i, --sz) {
			if (DRM_COPY_FROM_USER_UNCHECKED( &cmd, &buffer[i], 
							  sizeof(cmd))) {
				return DRM_ERR( EINVAL );
			}
			OUT_RING(cmd);
		}
		ADVANCE_LP_RING();
	}

	return 0;
}

static int i915_emit_box( drm_device_t *dev,
			  drm_clip_rect_t *boxes,
			  int i,
			  int DR1,
			  int DR4)
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
   	drm_clip_rect_t box;
   	RING_LOCALS;

	if (DRM_COPY_FROM_USER_UNCHECKED( &box, &boxes[i], sizeof(box) )) {
		return EFAULT;
	}

	if (box.y2 <= box.y1 ||
	    box.x2 <= box.x1 ||
	    box.y2 <= 0 ||
	    box.x2 <= 0) {
		DRM_ERROR("Bad box %d,%d..%d,%d\n",
			  box.x1, box.y1, box.x2, box.y2);
		return DRM_ERR(EINVAL);
	}
				

	BEGIN_LP_RING(6);
	OUT_RING( GFX_OP_DRAWRECT_INFO );
	OUT_RING( DR1 );
	OUT_RING( (box.x1 & 0xffff) | (box.y1<<16) );
	OUT_RING( ((box.x2-1) & 0xffff) | ((box.y2-1)<<16) );
	OUT_RING( DR4 );
	OUT_RING( 0 );
	ADVANCE_LP_RING();
	
	return 0;
}


static int i915_dispatch_cmdbuffer(drm_device_t *dev, 
				   drm_i915_cmdbuffer_t *cmd )
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
   	int nbox = cmd->num_cliprects;
	int i = 0, count, ret;
   	RING_LOCALS;

	if (cmd->sz & 0x3) {
		DRM_ERROR("alignment");
		return DRM_ERR(EINVAL);
	}
		
   	i915_kernel_lost_context(dev);

	count = nbox ? nbox : 1;

	for (i = 0 ; i < count ; i++) {
		if (i < nbox) {
			ret = i915_emit_box( dev, cmd->cliprects, i, 
					     cmd->DR1, cmd->DR4);
			if (ret) 
				return ret;
		}

		ret = i915_emit_cmds( dev, (int *)cmd->buf, cmd->sz / 4 );
		if (ret) 
			return ret;
	}

	return 0;
}


static int i915_dispatch_batchbuffer(drm_device_t *dev, 
				    drm_i915_batchbuffer_t *batch )
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
   	drm_clip_rect_t box, *boxes = batch->cliprects;
   	int nbox = batch->num_cliprects;
	int i = 0, count;
   	RING_LOCALS;

	if ((batch->start | batch->used) & 0x7) {
		DRM_ERROR("alignment");
		return DRM_ERR(EINVAL);
	}
		
   	i915_kernel_lost_context(dev);

	count = nbox ? nbox : 1;

	for (i = 0 ; i < count ; i++) {
		if (i < nbox) {
			int ret = i915_emit_box( dev, boxes, i,
						 batch->DR1, batch->DR4);
			if (ret) 
				return ret;
		}

		if (dev_priv->use_mi_batchbuffer_start) {
			BEGIN_LP_RING(2);
			OUT_RING( MI_BATCH_BUFFER_START | (2<<6) );
			OUT_RING( batch->start | MI_BATCH_NON_SECURE );
			ADVANCE_LP_RING();
		} 
		else {
			BEGIN_LP_RING(4);
			OUT_RING( MI_BATCH_BUFFER );
			OUT_RING( batch->start | MI_BATCH_NON_SECURE );
			OUT_RING( batch->start + batch->used - 4 );
			OUT_RING( 0 );
			ADVANCE_LP_RING();
		}
	}

	
	dev_priv->sarea_priv->last_enqueue = dev_priv->counter++;

	BEGIN_LP_RING(4);
	OUT_RING( CMD_STORE_DWORD_IDX );
	OUT_RING( 20 );
	OUT_RING( dev_priv->counter );
	OUT_RING( 0 );
	ADVANCE_LP_RING();

	return 0;
}

static int i915_dispatch_flip( drm_device_t *dev )
{
   	drm_i915_private_t *dev_priv = dev->dev_private;
	RING_LOCALS;

	DRM_DEBUG( "%s: page=%d pfCurrentPage=%d\n", 
		   __FUNCTION__, 
		   dev_priv->current_page,
		   dev_priv->sarea_priv->pf_current_page);

  	i915_kernel_lost_context(dev);


	BEGIN_LP_RING( 2 );
    	OUT_RING( INST_PARSER_CLIENT | INST_OP_FLUSH | INST_FLUSH_MAP_CACHE ); 
	OUT_RING( 0 );
	ADVANCE_LP_RING();

	BEGIN_LP_RING( 6 );
	OUT_RING( CMD_OP_DISPLAYBUFFER_INFO | ASYNC_FLIP );	
	OUT_RING( 0 );
	if ( dev_priv->current_page == 0 ) {
		OUT_RING( dev_priv->back_offset );
		dev_priv->current_page = 1;
	} else {
		OUT_RING( dev_priv->front_offset );
		dev_priv->current_page = 0;
	}
	OUT_RING(0);
	ADVANCE_LP_RING();


	BEGIN_LP_RING( 2 );
	OUT_RING( MI_WAIT_FOR_EVENT |
		  MI_WAIT_FOR_PLANE_A_FLIP );
	OUT_RING( 0 );
	ADVANCE_LP_RING();
	

	dev_priv->sarea_priv->last_enqueue = dev_priv->counter++;

	BEGIN_LP_RING(4);
	OUT_RING( CMD_STORE_DWORD_IDX );
	OUT_RING( 20 );
	OUT_RING( dev_priv->counter );
	OUT_RING( 0 );
	ADVANCE_LP_RING();

	dev_priv->sarea_priv->pf_current_page = dev_priv->current_page;
	return 0;
}


static int i915_quiescent(drm_device_t *dev)
{
   	drm_i915_private_t *dev_priv = dev->dev_private;

  	i915_kernel_lost_context(dev);
	return i915_wait_ring( dev, dev_priv->ring.Size - 8, __FUNCTION__ );
}


int i915_flush_ioctl( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;

   	if(!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
		DRM_ERROR("i915_flush_ioctl called without lock held\n");
		return DRM_ERR(EINVAL);
	}

    	return i915_quiescent(dev); 
}

int i915_batchbuffer( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;
   	drm_i915_private_t *dev_priv = (drm_i915_private_t *)dev->dev_private;
      	u32 *hw_status = dev_priv->hw_status_page;
   	drm_i915_sarea_t *sarea_priv = (drm_i915_sarea_t *) 
     					dev_priv->sarea_priv; 
	drm_i915_batchbuffer_t batch;
	int ret;

	if (!dev_priv->allow_batchbuffer) {
		DRM_ERROR("Batchbuffer ioctl disabled\n");
		return DRM_ERR(EINVAL);
	}

	DRM_COPY_FROM_USER_IOCTL( batch, (drm_i915_batchbuffer_t *)data, 
				  sizeof(batch) );

	DRM_DEBUG("i915 batchbuffer, start %x used %d cliprects %d\n",
		  batch.start, batch.used, batch.num_cliprects);


   	if(!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
		DRM_ERROR("i915_batchbuffer called without lock held\n");
		return DRM_ERR(EINVAL);
	}

	if (batch.num_cliprects && DRM_VERIFYAREA_READ(batch.cliprects, 
						       batch.num_cliprects *
						       sizeof(drm_clip_rect_t)))
		return DRM_ERR(EFAULT);

	ret = i915_dispatch_batchbuffer( dev, &batch );

   	sarea_priv->last_dispatch = (int) hw_status[5];   
	return ret;
}

int i915_cmdbuffer( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;
   	drm_i915_private_t *dev_priv = (drm_i915_private_t *)dev->dev_private;
      	u32 *hw_status = dev_priv->hw_status_page;
   	drm_i915_sarea_t *sarea_priv = (drm_i915_sarea_t *) 
		dev_priv->sarea_priv; 
	drm_i915_cmdbuffer_t cmdbuf;
	int ret;

	DRM_COPY_FROM_USER_IOCTL( cmdbuf, (drm_i915_cmdbuffer_t *)data, 
				  sizeof(cmdbuf) );

	DRM_DEBUG("i915 cmdbuffer, buf %p sz %d cliprects %d\n",
		  cmdbuf.buf, cmdbuf.sz, cmdbuf.num_cliprects);


   	if(!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
		DRM_ERROR("i915_cmdbuffer called without lock held\n");
		return DRM_ERR(EINVAL);
	}

	if (cmdbuf.num_cliprects && 
	    DRM_VERIFYAREA_READ(cmdbuf.cliprects, 
				cmdbuf.num_cliprects *
				sizeof(drm_clip_rect_t))) {
		DRM_ERROR("Fault accessing cliprects\n");
		return DRM_ERR(EFAULT);
	}

	ret = i915_dispatch_cmdbuffer( dev, &cmdbuf );
	if (ret) {
		DRM_ERROR("i915_dispatch_cmdbuffer failed\n");
		return ret;
	}

   	sarea_priv->last_dispatch = (int) hw_status[5];   
	return 0;
}


int i915_do_cleanup_pageflip( drm_device_t *dev )
{
	drm_i915_private_t *dev_priv = dev->dev_private;

	DRM_DEBUG("%s\n", __FUNCTION__);
	if (dev_priv->current_page != 0)
		i915_dispatch_flip( dev );

	return 0;
}

int i915_flip_bufs( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;

	DRM_DEBUG("%s\n", __FUNCTION__);
   	if(!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
		DRM_ERROR("i915_flip_buf called without lock held\n");
		return DRM_ERR(EINVAL);
	}

	return i915_dispatch_flip( dev );
}


int i915_getparam( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;
	drm_i915_private_t *dev_priv = dev->dev_private;
	drm_i915_getparam_t param;
	int value;

	if ( !dev_priv ) {
		DRM_ERROR( "%s called with no initialization\n", __FUNCTION__ );
		return DRM_ERR(EINVAL);
	}

	DRM_COPY_FROM_USER_IOCTL(param, (drm_i915_getparam_t *)data, 
				 sizeof(param));

	switch( param.param ) {
	case I915_PARAM_IRQ_ACTIVE:
		value = dev->irq ? 1 : 0;
		break;
	case I915_PARAM_ALLOW_BATCHBUFFER:
		value = dev_priv->allow_batchbuffer ? 1 : 0;
		break;
	default:
		DRM_ERROR("Unkown parameter %d\n", param.param);
		return DRM_ERR(EINVAL);
	}

	if ( DRM_COPY_TO_USER( param.value, &value, sizeof(int) ) ) {
		DRM_ERROR("DRM_COPY_TO_USER failed\n");
		return DRM_ERR(EFAULT);
	}
	
	return 0;
}


int i915_setparam( DRM_IOCTL_ARGS )
{
	DRM_DEVICE;
	drm_i915_private_t *dev_priv = dev->dev_private;
	drm_i915_setparam_t param;

	if ( !dev_priv ) {
		DRM_ERROR( "%s called with no initialization\n", __FUNCTION__ );
		return DRM_ERR(EINVAL);
	}

	DRM_COPY_FROM_USER_IOCTL( param, (drm_i915_setparam_t *)data, 
				  sizeof(param) );

	switch( param.param ) {
	case I915_SETPARAM_USE_MI_BATCHBUFFER_START:
		dev_priv->use_mi_batchbuffer_start = param.value;
		break;
	case I915_SETPARAM_TEX_LRU_LOG_GRANULARITY:
		dev_priv->tex_lru_log_granularity = param.value;
		break;
	case I915_SETPARAM_ALLOW_BATCHBUFFER:
		dev_priv->allow_batchbuffer = param.value;
		break;
	default:
		DRM_ERROR("unknown parameter %d\n", param.param);
		return DRM_ERR(EINVAL);
	}


	return 0;
}