path: root/hw/xfree86/os-support/bsd/i386_video.c

/* $XFree86: xc/programs/Xserver/hw/xfree86/os-support/bsd/i386_video.c,v 1.4 2003/09/24 02:43:34 dawes Exp $ */
/*
 * Copyright 1992 by Rich Murphey <Rich@Rice.edu>
 * Copyright 1993 by David Wexelblat <dwex@goblin.org>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the names of Rich Murphey and David Wexelblat 
 * not be used in advertising or publicity pertaining to distribution of 
 * the software without specific, written prior permission.  Rich Murphey and
 * David Wexelblat make no representations about the suitability of this 
 * software for any purpose.  It is provided "as is" without express or 
 * implied warranty.
 *
 * RICH MURPHEY AND DAVID WEXELBLAT DISCLAIM ALL WARRANTIES WITH REGARD TO 
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND 
 * FITNESS, IN NO EVENT SHALL RICH MURPHEY OR DAVID WEXELBLAT BE LIABLE FOR 
 * ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER 
 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF 
 * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

/* $XConsortium: bsd_video.c /main/10 1996/10/25 11:37:57 kaleb $ */

#include "X.h"
#include "xf86.h"
#include "xf86Priv.h"

#ifdef HAS_MTRR_SUPPORT
#ifndef __NetBSD__
#include <sys/types.h>
#include <sys/memrange.h>
#else
#include "memrange.h"
#endif
#define X_MTRR_ID "XFree86"
#endif

#if defined(HAS_MTRR_BUILTIN) && defined(__NetBSD__)
#include <machine/mtrr.h>
#include <machine/sysarch.h>
#include <sys/queue.h>
#endif

#include "xf86_OSlib.h"
#include "xf86OSpriv.h"

#if defined(__NetBSD__) && !defined(MAP_FILE)
#define MAP_FLAGS MAP_SHARED
#else
#define MAP_FLAGS (MAP_FILE | MAP_SHARED)
#endif

#ifndef MAP_FAILED
#define MAP_FAILED ((caddr_t)-1)
#endif

#ifdef __OpenBSD__
#define SYSCTL_MSG "\tCheck that you have set 'machdep.allowaperture=1'\n"\
		   "\tin /etc/sysctl.conf and reboot your machine\n" \
		   "\trefer to xf86(4) for details"
#define SYSCTL_MSG2 \
		"Check that you have set 'machdep.allowaperture=2'\n" \
		"\tin /etc/sysctl.conf and reboot your machine\n" \
		"\trefer to xf86(4) for details"
#endif

/***************************************************************************/
/* Video Memory Mapping section                                            */
/***************************************************************************/

static Bool useDevMem = FALSE;
static int  devMemFd = -1;

#ifdef HAS_APERTURE_DRV
#define DEV_APERTURE "/dev/xf86"
#endif
#define DEV_MEM "/dev/mem"

static pointer mapVidMem(int, unsigned long, unsigned long, int);
static void unmapVidMem(int, pointer, unsigned long);

#ifdef HAS_MTRR_SUPPORT
static pointer setWC(int, unsigned long, unsigned long, Bool, MessageType);
static void undoWC(int, pointer);
static Bool cleanMTRR(void);
#endif
#if defined(HAS_MTRR_BUILTIN) && defined(__NetBSD__)
static pointer NetBSDsetWC(int, unsigned long, unsigned long, Bool,
			   MessageType);
static void NetBSDundoWC(int, pointer);
#endif


/*
 * Check if /dev/mem can be mmap'd.  If it can't print a warning when
 * "warn" is TRUE.
 */
static void
checkDevMem(Bool warn)
{
	static Bool devMemChecked = FALSE;
	int fd;
	pointer base;

	if (devMemChecked)
	    return;
	devMemChecked = TRUE;

	if ((fd = open(DEV_MEM, O_RDWR)) >= 0)
	{
	    /* Try to map a page at the VGA address */
	    base = mmap((caddr_t)0, 4096, PROT_READ | PROT_WRITE,
				 MAP_FLAGS, fd, (off_t)0xA0000);
	
	    if (base != MAP_FAILED)
	    {
		munmap((caddr_t)base, 4096);
		devMemFd = fd;
		useDevMem = TRUE;
		return;
	    } else {
		/* This should not happen */
		if (warn)
		{
		    xf86Msg(X_WARNING, "checkDevMem: failed to mmap %s (%s)\n",
			    DEV_MEM, strerror(errno));
		}
		useDevMem = FALSE;
		return;
	    }
	}
#ifndef HAS_APERTURE_DRV
	if (warn)
	{ 
	    xf86Msg(X_WARNING, "checkDevMem: failed to open %s (%s)\n",
		    DEV_MEM, strerror(errno));
	} 
	useDevMem = FALSE;
	return;
#else
	/* Failed to open /dev/mem, try the aperture driver */
	if ((fd = open(DEV_APERTURE, O_RDWR)) >= 0)
	{
	    /* Try to map a page at the VGA address */
	    base = mmap((caddr_t)0, 4096, PROT_READ | PROT_WRITE,
			     MAP_FLAGS, fd, (off_t)0xA0000);
	
	    if (base != MAP_FAILED)
	    {
		munmap((caddr_t)base, 4096);
		devMemFd = fd;
		useDevMem = TRUE;
		xf86Msg(X_INFO, "checkDevMem: using aperture driver %s\n",
		        DEV_APERTURE);
		return;
	    } else {

		if (warn)
		{
		    xf86Msg(X_WARNING, "checkDevMem: failed to mmap %s (%s)\n",
			    DEV_APERTURE, strerror(errno));
		}
	    }
	} else {
	    if (warn)
	    {
#ifndef __OpenBSD__
		xf86Msg(X_WARNING, "checkDevMem: failed to open %s and %s\n"
			"\t(%s)\n", DEV_MEM, DEV_APERTURE, strerror(errno));
#else /* __OpenBSD__ */
		xf86Msg(X_WARNING, "checkDevMem: failed to open %s and %s\n"
			"\t(%s)\n%s", DEV_MEM, DEV_APERTURE, strerror(errno),
			SYSCTL_MSG);
#endif /* __OpenBSD__ */
	    }
	}
	
	useDevMem = FALSE;
	return;

#endif
}

void
xf86OSInitVidMem(VidMemInfoPtr pVidMem)
{
	checkDevMem(TRUE);
	pVidMem->linearSupported = useDevMem;
	pVidMem->mapMem = mapVidMem;
	pVidMem->unmapMem = unmapVidMem;

#ifdef HAS_MTRR_SUPPORT
	if (useDevMem) {
		if (cleanMTRR()) {
			pVidMem->setWC = setWC;
			pVidMem->undoWC = undoWC;
		}
	}
#endif
#if defined(HAS_MTRR_BUILTIN) && defined(__NetBSD__)
	pVidMem->setWC = NetBSDsetWC;
	pVidMem->undoWC = NetBSDundoWC;
#endif
	pVidMem->initialised = TRUE;
}

static pointer
mapVidMem(int ScreenNum, unsigned long Base, unsigned long Size, int flags)
{
	pointer base;

	checkDevMem(FALSE);

	if (useDevMem)
	{
	    if (devMemFd < 0) 
	    {
		FatalError("xf86MapVidMem: failed to open %s (%s)",
			   DEV_MEM, strerror(errno));
	    }
	    base = mmap((caddr_t)0, Size,
			(flags & VIDMEM_READONLY) ?
			 PROT_READ : (PROT_READ | PROT_WRITE),
			MAP_FLAGS, devMemFd, (off_t)Base);
	    if (base == MAP_FAILED)
	    {
		FatalError("%s: could not mmap %s [s=%lx,a=%lx] (%s)",
			   "xf86MapVidMem", DEV_MEM, Size, Base, 
			   strerror(errno));
	    }
	    return(base);
	}
		
	/* else, mmap /dev/vga */
	if ((unsigned long)Base < 0xA0000 || (unsigned long)Base >= 0xC0000)
	{
		FatalError("%s: Address 0x%lx outside allowable range",
			   "xf86MapVidMem", Base);
	}
	base = mmap(0, Size,
		    (flags & VIDMEM_READONLY) ?
		     PROT_READ : (PROT_READ | PROT_WRITE),
		    MAP_FLAGS, xf86Info.screenFd,
		    (unsigned long)Base - 0xA0000
	    );
	if (base == MAP_FAILED)
	{
	    FatalError("xf86MapVidMem: Could not mmap /dev/vga (%s)",
		       strerror(errno));
	}
	return(base);
}

static void
unmapVidMem(int ScreenNum, pointer Base, unsigned long Size)
{
	munmap((caddr_t)Base, Size);
}

/*
 * Read BIOS via mmap()ing DEV_MEM
 */

int
xf86ReadBIOS(unsigned long Base, unsigned long Offset, unsigned char *Buf,
	     int Len)
{
	unsigned char *ptr;
	int psize;
	int mlen;

	checkDevMem(TRUE);
	if (devMemFd == -1) {
	    return(-1);
	}

	psize = xf86getpagesize();
	Offset += Base & (psize - 1);
	Base &= ~(psize - 1);
	mlen = (Offset + Len + psize - 1) & ~(psize - 1);
	ptr = (unsigned char *)mmap((caddr_t)0, mlen, PROT_READ,
					MAP_SHARED, devMemFd, (off_t)Base);
	if ((long)ptr == -1)
	{
		xf86Msg(X_WARNING, 
			"xf86ReadBIOS: %s mmap[s=%x,a=%lx,o=%lx] failed (%s)\n",
			DEV_MEM, Len, Base, Offset, strerror(errno));
#ifdef __OpenBSD__
		if (Base < 0xa0000) {
		    xf86Msg(X_WARNING, SYSCTL_MSG2);
		} 
#endif
		return(-1);
	}
#ifdef DEBUG
	ErrorF("xf86ReadBIOS: BIOS at 0x%08x has signature 0x%04x\n",
		Base, ptr[0] | (ptr[1] << 8));
#endif
	(void)memcpy(Buf, (void *)(ptr + Offset), Len);
	(void)munmap((caddr_t)ptr, mlen);
#ifdef DEBUG
	xf86MsgVerb(X_INFO, 3, "xf86ReadBIOS(%x, %x, Buf, %x)"
		"-> %02x %02x %02x %02x...\n",
		Base, Offset, Len, Buf[0], Buf[1], Buf[2], Buf[3]);
#endif
	return(Len);
}


#ifdef USE_I386_IOPL
/***************************************************************************/
/* I/O Permissions section                                                 */
/***************************************************************************/

static Bool ExtendedEnabled = FALSE;

void
xf86EnableIO()
{
	if (ExtendedEnabled)
		return;

	if (i386_iopl(TRUE) < 0)
	{
#ifndef __OpenBSD__
		FatalError("%s: Failed to set IOPL for extended I/O",
			   "xf86EnableIO");
#else
		FatalError("%s: Failed to set IOPL for extended I/O\n%s",
			   "xf86EnableIO", SYSCTL_MSG);
#endif
	}
	ExtendedEnabled = TRUE;

	return;
}
	
void
xf86DisableIO()
{
	if (!ExtendedEnabled)
		return;

	i386_iopl(FALSE);
	ExtendedEnabled = FALSE;

	return;
}

#endif /* USE_I386_IOPL */

#ifdef USE_DEV_IO
static int IoFd = -1;

void
xf86EnableIO()
{
	if (IoFd >= 0)
		return;

	if ((IoFd = open("/dev/io", O_RDWR)) == -1)
	{
		FatalError("xf86EnableIO: "
				"Failed to open /dev/io for extended I/O");
	}
	return;
}

void
xf86DisableIO()
{
	if (IoFd < 0)
		return;

	close(IoFd);
	IoFd = -1;
	return;
}

#endif


/***************************************************************************/
/* Interrupt Handling section                                              */
/***************************************************************************/

Bool
xf86DisableInterrupts()
{

#ifdef __GNUC__
	__asm__ __volatile__("cli");
#else 
	asm("cli");
#endif /* __GNUC__ */

	return(TRUE);
}

void
xf86EnableInterrupts()
{

#ifdef __GNUC__
	__asm__ __volatile__("sti");
#else 
	asm("sti");
#endif /* __GNUC__ */

	return;
}


#ifdef __NetBSD__
/***************************************************************************/
/* Set TV output mode                                                      */
/***************************************************************************/
void
xf86SetTVOut(int mode)
{    
    switch (xf86Info.consType)
    {
#ifdef PCCONS_SUPPORT
	case PCCONS:{

	    if (ioctl (xf86Info.consoleFd, CONSOLE_X_TV_ON, &mode) < 0)
	    {
		xf86Msg(X_WARNING,
		    "xf86SetTVOut: Could not set console to TV output, %s\n",
		    strerror(errno));
	    }
	}
	break;
#endif /* PCCONS_SUPPORT */

	default:
	    FatalError("Xf86SetTVOut: Unsupported console");
	    break; 
    }
    return;
}

void
xf86SetRGBOut()
{    
    switch (xf86Info.consType)
    {
#ifdef PCCONS_SUPPORT
	case PCCONS:{
	    
	    if (ioctl (xf86Info.consoleFd, CONSOLE_X_TV_OFF, 0) < 0)
	    {
		xf86Msg(X_WARNING,
		    "xf86SetTVOut: Could not set console to RGB output, %s\n",
		    strerror(errno));
	    }
	}
	break;
#endif /* PCCONS_SUPPORT */

	default:
	    FatalError("Xf86SetTVOut: Unsupported console");
	    break; 
    }
    return;
}
#endif


#ifdef HAS_MTRR_SUPPORT
/* memory range (MTRR) support for FreeBSD */

/*
 * This code is experimental.  Some parts may be overkill, and other parts
 * may be incomplete.
 */

/*
 * getAllRanges returns the full list of memory ranges with attributes set.
 */

static struct mem_range_desc *
getAllRanges(int *nmr)
{
	struct mem_range_desc *mrd;
	struct mem_range_op mro;

	/*
	 * Find how many ranges there are.  If this fails, then the kernel
	 * probably doesn't have MTRR support.
	 */
	mro.mo_arg[0] = 0;
	if (ioctl(devMemFd, MEMRANGE_GET, &mro))
		return NULL;
	*nmr = mro.mo_arg[0];
	mrd = xnfalloc(*nmr * sizeof(struct mem_range_desc));
	mro.mo_arg[0] = *nmr;
	mro.mo_desc = mrd;
	if (ioctl(devMemFd, MEMRANGE_GET, &mro)) {
		xfree(mrd);
		return NULL;
	}
	return mrd;
}

/*
 * cleanMTRR removes any memory attribute that may be left by a previous
 * X server.  Normally there won't be any, but this takes care of the
 * case where a server crashed without being able finish cleaning up.
 */

static Bool
cleanMTRR()
{
	struct mem_range_desc *mrd;
	struct mem_range_op mro;
	int nmr, i;

	/* This shouldn't happen */
	if (devMemFd < 0)
		return FALSE;

	if (!(mrd = getAllRanges(&nmr)))
		return FALSE;

	for (i = 0; i < nmr; i++) {
		if (strcmp(mrd[i].mr_owner, X_MTRR_ID) == 0 &&
		    (mrd[i].mr_flags & MDF_ACTIVE)) {
#ifdef DEBUG
			ErrorF("Clean for (0x%lx,0x%lx)\n",
				(unsigned long)mrd[i].mr_base,
				(unsigned long)rd[i].mr_len);
#endif
			if (mrd[i].mr_flags & MDF_FIXACTIVE) {
				mro.mo_arg[0] = MEMRANGE_SET_UPDATE;
				mrd[i].mr_flags = MDF_UNCACHEABLE;
			} else {
				mro.mo_arg[0] = MEMRANGE_SET_REMOVE;
			}
			mro.mo_desc = mrd + i;
			ioctl(devMemFd, MEMRANGE_SET, &mro);
		}
	}
#ifdef DEBUG
	sleep(10);
#endif
	xfree(mrd);
	return TRUE;
}

typedef struct x_RangeRec {
	struct mem_range_desc	mrd;
	Bool			wasWC;
	struct x_RangeRec *	next;
} RangeRec, *RangePtr;

static void
freeRangeList(RangePtr range)
{
	RangePtr rp;

	while (range) {
		rp = range;
		range = rp->next;
		xfree(rp);
	}
}

static RangePtr
dupRangeList(RangePtr list)
{
	RangePtr new = NULL, rp, p;

	rp = list;
	while (rp) {
		p = xnfalloc(sizeof(RangeRec));
		*p = *rp;
		p->next = new;
		new = p;
		rp = rp->next;
	}
	return new;
}

static RangePtr
sortRangeList(RangePtr list)
{
	RangePtr rp1, rp2, copy, sorted = NULL, minp, prev, minprev;
	unsigned long minBase;

	/* Sort by base address */
	rp1 = copy = dupRangeList(list);
	while (rp1) {
		minBase = rp1->mrd.mr_base;
		minp = rp1;
		minprev = NULL;
		prev = rp1;
		rp2 = rp1->next;
		while (rp2) {
			if (rp2->mrd.mr_base < minBase) {
				minBase = rp2->mrd.mr_base;
				minp = rp2;
				minprev = prev;
			}
			prev = rp2;
			rp2 = rp2->next;
		}
		if (minprev) {
			minprev->next = minp->next;
			rp1 = copy;
		} else {
			rp1 = minp->next;
		}
		minp->next = sorted;
		sorted = minp;
	}
	return sorted;
}

/*
 * findRanges returns a list of ranges that overlap the specified range.
 */

static void
findRanges(unsigned long base, unsigned long size, RangePtr *ucp, RangePtr *wcp)
{
	struct mem_range_desc *mrd;
	int nmr, i;
	RangePtr rp, *p;
	
	if (!(mrd = getAllRanges(&nmr)))
		return;

	for (i = 0; i < nmr; i++) {
		if ((mrd[i].mr_flags & MDF_ACTIVE) &&
		    mrd[i].mr_base < base + size &&
		    mrd[i].mr_base + mrd[i].mr_len > base) {
			if (mrd[i].mr_flags & MDF_WRITECOMBINE)
				p = wcp;
			else if (mrd[i].mr_flags & MDF_UNCACHEABLE)
				p = ucp;
			else
				continue;
			rp = xnfalloc(sizeof(RangeRec));
			rp->mrd = mrd[i];
			rp->next = *p;
			*p = rp;
		}
	}
	xfree(mrd);
}

/*
 * This checks if the existing overlapping ranges fully cover the requested
 * range.  Is this overkill?
 */

static Bool
fullCoverage(unsigned long base, unsigned long size, RangePtr overlap)
{
	RangePtr rp1, sorted = NULL;
	unsigned long end;

	sorted = sortRangeList(overlap);
	/* Look for gaps */
	rp1 = sorted;
	end = base + size;
	while (rp1) {
		if (rp1->mrd.mr_base > base) {
			freeRangeList(sorted);
			return FALSE;
		} else {
			base = rp1->mrd.mr_base + rp1->mrd.mr_len;
		}
		if (base >= end) {
			freeRangeList(sorted);
			return TRUE;
		}
		rp1 = rp1->next;
	}
	freeRangeList(sorted);
	return FALSE;
}

static pointer
addWC(int screenNum, unsigned long base, unsigned long size, MessageType from)
{
	RangePtr uc = NULL, wc = NULL, retlist = NULL;
	struct mem_range_desc mrd;
	struct mem_range_op mro;

	findRanges(base, size, &uc, &wc);

	/* See of the full range is already WC */
	if (!uc && fullCoverage(base, size, wc)) {
		xf86DrvMsg(screenNum, from, 
		   "Write-combining range (0x%lx,0x%lx) was already set\n",
		    base, size);
		return NULL;
	}

	/* Otherwise, try to add the new range */
	mrd.mr_base = base;
	mrd.mr_len = size;
	strcpy(mrd.mr_owner, X_MTRR_ID);
	mrd.mr_flags = MDF_WRITECOMBINE;
	mro.mo_desc = &mrd;
	mro.mo_arg[0] = MEMRANGE_SET_UPDATE;
	if (ioctl(devMemFd, MEMRANGE_SET, &mro)) {
		xf86DrvMsg(screenNum, X_WARNING,
			   "Failed to set write-combining range "
			   "(0x%lx,0x%lx)\n", base, size);
		return NULL;
	} else {
		xf86DrvMsg(screenNum, from,
			   "Write-combining range (0x%lx,0x%lx)\n", base, size);
		retlist = xnfalloc(sizeof(RangeRec));
		retlist->mrd = mrd;
		retlist->wasWC = FALSE;
		retlist->next = NULL;
		return retlist;
	}
}

static pointer
delWC(int screenNum, unsigned long base, unsigned long size, MessageType from)
{
	RangePtr uc = NULL, wc = NULL, retlist = NULL;
	struct mem_range_desc mrd;
	struct mem_range_op mro;

	findRanges(base, size, &uc, &wc);

	/*
	 * See of the full range is already not WC, or if there is full
	 * coverage from UC ranges.
	 */
	if (!wc || fullCoverage(base, size, uc)) {
		xf86DrvMsg(screenNum, from, 
		   "Write-combining range (0x%lx,0x%lx) was already clear\n",
		    base, size);
		return NULL;
	}

	/* Otherwise, try to add the new range */
	mrd.mr_base = base;
	mrd.mr_len = size;
	strcpy(mrd.mr_owner, X_MTRR_ID);
	mrd.mr_flags = MDF_UNCACHEABLE;
	mro.mo_desc = &mrd;
	mro.mo_arg[0] = MEMRANGE_SET_UPDATE;
	if (ioctl(devMemFd, MEMRANGE_SET, &mro)) {
		xf86DrvMsg(screenNum, X_WARNING,
			   "Failed to remove write-combining range "
			   "(0x%lx,0x%lx)\n", base, size);
		/* XXX Should then remove all of the overlapping WC ranges */
		return NULL;
	} else {
		xf86DrvMsg(screenNum, from,
			   "Removed Write-combining range (0x%lx,0x%lx)\n",
			   base, size);
		retlist = xnfalloc(sizeof(RangeRec));
		retlist->mrd = mrd;
		retlist->wasWC = TRUE;
		retlist->next = NULL;
		return retlist;
	}
}

static pointer
setWC(int screenNum, unsigned long base, unsigned long size, Bool enable,
	MessageType from)
{
	if (enable)
		return addWC(screenNum, base, size, from);
	else
		return delWC(screenNum, base, size, from);
}

static void
undoWC(int screenNum, pointer list)
{
	RangePtr rp;
	struct mem_range_op mro;
	Bool failed;

	rp = list;
	while (rp) {
#ifdef DEBUG
		ErrorF("Undo for (0x%lx,0x%lx), %d\n",
			(unsigned long)rp->mrd.mr_base,
			(unsigned long)rp->mrd.mr_len, rp->wasWC);
#endif
		failed = FALSE;
		if (rp->wasWC) {
			mro.mo_arg[0] = MEMRANGE_SET_UPDATE;
			rp->mrd.mr_flags = MDF_WRITECOMBINE;
			strcpy(rp->mrd.mr_owner, "unknown");
		} else {
			mro.mo_arg[0] = MEMRANGE_SET_REMOVE;
		}
		mro.mo_desc = &rp->mrd;

		if (ioctl(devMemFd, MEMRANGE_SET, &mro)) {
			if (!rp->wasWC) {
				mro.mo_arg[0] = MEMRANGE_SET_UPDATE;
				rp->mrd.mr_flags = MDF_UNCACHEABLE;
				strcpy(rp->mrd.mr_owner, "unknown");
				if (ioctl(devMemFd, MEMRANGE_SET, &mro))
					failed = TRUE;
			} else
				failed = TRUE;
		}
		if (failed) {
			xf86DrvMsg(screenNum, X_WARNING,
				"Failed to restore MTRR range (0x%lx,0x%lx)\n",
				(unsigned long)rp->mrd.mr_base,
				(unsigned long)rp->mrd.mr_len);
		}
		rp = rp->next;
	}
}

#endif /* HAS_MTRR_SUPPORT */


#if defined(HAS_MTRR_BUILTIN) && defined(__NetBSD__)
static pointer
NetBSDsetWC(int screenNum, unsigned long base, unsigned long size, Bool enable,
	    MessageType from)
{
	struct mtrr *mtrrp;
	int n;

	xf86DrvMsg(screenNum, X_WARNING,
		   "%s MTRR %lx - %lx\n", enable ? "set" : "remove",
		   base, (base + size));

	mtrrp = xnfalloc(sizeof (struct mtrr));
	mtrrp->base = base;
	mtrrp->len = size;
	mtrrp->type = MTRR_TYPE_WC;

	/*
	 * MTRR_PRIVATE will make this MTRR get reset automatically
	 * if this process exits, so we have no need for an explicit
	 * cleanup operation when starting a new server.
	 */

	if (enable)
		mtrrp->flags = MTRR_VALID | MTRR_PRIVATE;
	else
		mtrrp->flags = 0;
	n = 1;

	if (i386_set_mtrr(mtrrp, &n) < 0) {
		xfree(mtrrp);
		return NULL;
	}
	return mtrrp;
}

static void
NetBSDundoWC(int screenNum, pointer list)
{
	struct mtrr *mtrrp = (struct mtrr *)list;
	int n;

	if (mtrrp == NULL)
		return;
	n = 1;
	mtrrp->flags &= ~MTRR_VALID;
	i386_set_mtrr(mtrrp, &n);
	xfree(mtrrp);
}
#endif