path: root/nx-X11/programs/Xserver/os/WaitFor.c

/**************************************************************************/
/*                                                                        */
/* Copyright (c) 2001, 2011 NoMachine (http://www.nomachine.com)          */
/* Copyright (c) 2008-2014 Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>  */
/* Copyright (c) 2011-2016 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>*/
/* Copyright (c) 2014-2016 Mihai Moldovan <ionic@ionic.de>                */
/* Copyright (c) 2014-2016 Ulrich Sibiller <uli42@gmx.de>                 */
/* Copyright (c) 2015-2016 Qindel Group (http://www.qindel.com)           */
/*                                                                        */
/* nx-X11, NX protocol compression and NX extensions to this software     */
/* are copyright of the aforementioned persons and companies.             */
/*                                                                        */
/* Redistribution and use of the present software is allowed according    */
/* to terms specified in the file LICENSE which comes in the source       */
/* distribution.                                                          */
/*                                                                        */
/* All rights reserved.                                                   */
/*                                                                        */
/* NOTE: This software has received contributions from various other      */
/* contributors, only the core maintainers and supporters are listed as   */
/* copyright holders. Please contact us, if you feel you should be listed */
/* as copyright holder, as well.                                          */
/*                                                                        */
/**************************************************************************/

/***********************************************************

Copyright 1987, 1998  The Open Group

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.

The above copyright notice and this permission notice 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 THE
OPEN GROUP 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.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.


Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
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 name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL 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.

******************************************************************/

/*****************************************************************
 * OS Dependent input routines:
 *
 *  WaitForSomething
 *  TimerForce, TimerSet, TimerCheck, TimerFree
 *
 *****************************************************************/

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#ifdef WIN32
#include <nx-X11/Xwinsock.h>
#endif
#include <nx-X11/Xos.h>			/* for strings, fcntl, time */
#include <errno.h>
#include <stdio.h>
#include <nx-X11/X.h>
#include "misc.h"

#include "osdep.h"
#include <nx-X11/Xpoll.h>
#include "dixstruct.h"
#include "opaque.h"
#ifdef DPMSExtension
#include "dpmsproc.h"
#endif

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP)

static unsigned long startTimeInMillis;

#endif

#ifdef WIN32
/* Error codes from windows sockets differ from fileio error codes  */
#undef EINTR
#define EINTR WSAEINTR
#undef EINVAL
#define EINVAL WSAEINVAL
#undef EBADF
#define EBADF WSAENOTSOCK
/* Windows select does not set errno. Use GetErrno as wrapper for 
   WSAGetLastError */
#define GetErrno WSAGetLastError
#else
/* This is just a fallback to errno to hide the differences between unix and
   Windows in the code */
#define GetErrno() errno
#endif

/* modifications by raphael */
int
mffs(fd_mask mask)
{
    int i;

    if (!mask) return 0;
    i = 1;
    while (!(mask & 1))
    {
	i++;
	mask >>= 1;
    }
    return i;
}

#ifdef DPMSExtension
#define DPMS_SERVER
#include <nx-X11/extensions/dpms.h>
#endif

#ifdef XTESTEXT1
/*
 * defined in xtestext1dd.c
 */
extern int playback_on;
#endif /* XTESTEXT1 */

struct _OsTimerRec {
    OsTimerPtr		next;
    CARD32		expires;
    OsTimerCallback	callback;
    void *		arg;
};

static void DoTimer(OsTimerPtr timer, CARD32 now, OsTimerPtr *prev);
static OsTimerPtr timers = NULL;

/*****************
 * WaitForSomething:
 *     Make the server suspend until there is
 *	1. data from clients or
 *	2. input events available or
 *	3. ddx notices something of interest (graphics
 *	   queue ready, etc.) or
 *	4. clients that have buffered replies/events are ready
 *
 *     If the time between INPUT events is
 *     greater than ScreenSaverTime, the display is turned off (or
 *     saved, depending on the hardware).  So, WaitForSomething()
 *     has to handle this also (that's why the select() has a timeout.
 *     For more info on ClientsWithInput, see ReadRequestFromClient().
 *     pClientsReady is an array to store ready client->index values into.
 *****************/

int
WaitForSomething(int *pClientsReady)
{
    int i;
    struct timeval waittime, *wt;
    INT32 timeout = 0;
    fd_set clientsReadable;
    fd_set clientsWritable;
    int curclient;
    int selecterr;
    int nready;
    CARD32 now = 0;
    Bool    someReady = FALSE;
    Bool    someNotifyWriteReady = FALSE;

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
    fprintf(stderr, "WaitForSomething: Got called.\n");
#endif

    FD_ZERO(&clientsReadable);

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP)

    startTimeInMillis = GetTimeInMillis();

#endif

    /* We need a while loop here to handle 
       crashed connections and the screen saver timeout */
    while (1)
    {
	/* deal with any blocked jobs */
	if (workQueue)
	    ProcessWorkQueue();
	if (XFD_ANYSET (&ClientsWithInput))
	{
	    someReady = TRUE;
	    waittime.tv_sec = 0;
	    waittime.tv_usec = 0;
	    wt = &waittime;
	}
	if (someReady)
	{
	    XFD_COPYSET(&AllSockets, &LastSelectMask);
	    XFD_UNSET(&LastSelectMask, &ClientsWithInput);
	}
	else
	{
        wt = NULL;
	if (timers)
        {
            now = GetTimeInMillis();
	    timeout = timers->expires - now;
            if (timeout < 0)
                timeout = 0;
	    waittime.tv_sec = timeout / MILLI_PER_SECOND;
	    waittime.tv_usec = (timeout % MILLI_PER_SECOND) *
		               (1000000 / MILLI_PER_SECOND);
	    wt = &waittime;
	}
	XFD_COPYSET(&AllSockets, &LastSelectMask);
	}
	SmartScheduleStopTimer ();

	BlockHandler((void *)&wt, (void *)&LastSelectMask);
	if (NewOutputPending)
	    FlushAllOutput();
#ifdef XTESTEXT1
	/* XXX how does this interact with new write block handling? */
	if (playback_on) {
	    wt = &waittime;
	    XTestComputeWaitTime (&waittime);
	}
#endif /* XTESTEXT1 */

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP)

        /*
         * If caller has marked the first element of pClientsReady[],
         * bail out of select after a short timeout. We need this to
         * let the NX agent remove the splash screen when the timeout
         * is expired. A better option would be to use the existing
         * screen-saver timeout but it can be modified by clients, so
         * we would need a special handling. This hack is trivial and
         * keeps WaitForSomething() backward compatible with the exis-
         * ting servers.
         */

        if (pClientsReady[0] == -1)
        {
            unsigned long timeoutInMillis;

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP) && defined(NX_TRANS_DEBUG)
            fprintf(stderr, "WaitForSomething: pClientsReady[0] is [%d], pClientsReady[1] is [%d].\n",
                        pClientsReady[0], pClientsReady[1]);
#endif

            timeoutInMillis = GetTimeInMillis();

            if (timeoutInMillis - startTimeInMillis >= NX_TRANS_WAKEUP)
            {
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP) && defined(NX_TRANS_DEBUG)
                fprintf(stderr, "WaitForSomething: Returning 0 because of wakeup timeout.\n");
#endif
                return 0;
            }

            timeoutInMillis = NX_TRANS_WAKEUP - (timeoutInMillis - startTimeInMillis);

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP) && defined(NX_TRANS_DEBUG)
            fprintf(stderr, "WaitForSomething: Milliseconds to next wakeup are %ld.\n",
                        timeoutInMillis);
#endif
            if (wt == NULL || (wt -> tv_sec * MILLI_PER_SECOND +
                    wt -> tv_usec / MILLI_PER_SECOND) > timeoutInMillis)
            {
                if ((waittime.tv_sec * MILLI_PER_SECOND +
                        waittime.tv_usec / MILLI_PER_SECOND) > timeoutInMillis)
                {
                    waittime.tv_sec = timeoutInMillis / MILLI_PER_SECOND;
                    waittime.tv_usec = (timeoutInMillis * MILLI_PER_SECOND) %
                                            (MILLI_PER_SECOND * 1000);
                    wt = &waittime;
                }

#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP) && defined(NX_TRANS_DEBUG)
                fprintf(stderr, "WaitForSomething: Next wakeup timeout set to %ld milliseconds.\n",
                            (waittime.tv_sec * MILLI_PER_SECOND) +
                                (waittime.tv_usec / MILLI_PER_SECOND));
#endif
            }
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_WAKEUP) && defined(NX_TRANS_DEBUG)
            else
            {
                fprintf(stderr, "WaitForSomething: Using existing timeout of %ld milliseconds.\n",
                            (waittime.tv_sec * MILLI_PER_SECOND) +
                                (waittime.tv_usec / MILLI_PER_SECOND));
            }
#endif
        }
#endif

	/* keep this check close to select() call to minimize race */
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
	if (dispatchException)
	{
	    i = -1;

            fprintf(stderr, "WaitForSomething: Value of dispatchException is true. Set i = -1.\n");
	}
#else
        if (dispatchException)
            i = -1;
#endif
	else if (AnyWritesPending)
	{
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
            if (wt == NULL)
            {
                fprintf(stderr, "WaitForSomething: Executing select with LastSelectMask and "
                            "clientsWritable and null timeout.\n");
            }
            else
            {
                fprintf(stderr, "WaitForSomething: Executing select with LastSelectMask, "
                            "clientsWritable, %ld secs and %ld usecs.\n",
                                wt -> tv_sec, wt -> tv_usec);
            }
#endif
	     XFD_COPYSET(&ClientsWriteBlocked, &LastSelectWriteMask);
	     XFD_ORSET(&LastSelectWriteMask, &NotifyWriteFds, &LastSelectWriteMask);
	     i = Select(MaxClients, &LastSelectMask, &LastSelectWriteMask, NULL, wt);
	}
	else 
	{
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
            if (wt == NULL)
            {
                fprintf(stderr, "WaitForSomething: Executing select with LastSelectMask and null timeout.\n");
            }
            else
            {
                fprintf(stderr, "WaitForSomething: Executing select with LastSelectMask, %ld secs and %ld usecs.\n",
                            wt -> tv_sec, wt -> tv_usec);
            }
#endif
	    i = Select (MaxClients, &LastSelectMask, NULL, NULL, wt);
	}
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
        fprintf(stderr, "WaitForSomething: Bailed out with i = [%d] and errno = [%d].\n", i, errno);

        if (i < 0)
        {
            fprintf(stderr, "WaitForSomething: Error is [%s].\n", strerror(errno));
        }
#endif
	selecterr = GetErrno();
	WakeupHandler(i, (void *)&LastSelectMask);
#ifdef XTESTEXT1
	if (playback_on) {
	    i = XTestProcessInputAction (i, &waittime);
	}
#endif /* XTESTEXT1 */
	SmartScheduleStartTimer ();

	if (i <= 0) /* An error or timeout occurred */
	{
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
            if (dispatchException)
            {
                fprintf(stderr, "WaitForSomething: Returning 0 because of (dispatchException).\n");
                return 0;
            }
#else
            if (dispatchException)
                return 0;
#endif
	    if (i < 0) 
	    {
		if (selecterr == EBADF)    /* Some client disconnected */
		{
		    CheckConnections ();
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
                    if (! XFD_ANYSET (&AllClients))
                    {
                        fprintf(stderr, "WaitForSomething: Returning 0 because of (! XFD_ANYSET (&AllClients)).\n");
                        return 0;
                    }
#else
                    if (! XFD_ANYSET (&AllClients))
                        return 0;
#endif
		}
		else if (selecterr == EINVAL)
		{
		    FatalError("WaitForSomething(): select: errno=%d\n",
			selecterr);
            }
		else if (selecterr != EINTR)
		{
		    ErrorF("WaitForSomething(): select: errno=%d\n",
			selecterr);
		}
	    }
	    else if (someReady)
	    {
		/*
		 * If no-one else is home, bail quickly
		 */
		XFD_COPYSET(&ClientsWithInput, &LastSelectMask);
		XFD_COPYSET(&ClientsWithInput, &clientsReadable);
		break;
	    }
#if defined(NX_TRANS_SOCKET)
            if (*checkForInput[0] != *checkForInput[1])
            {
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
                fprintf(stderr, "WaitForSomething: Returning 0 because of (*checkForInput[0] != *checkForInput[1]).\n");
#endif
		return 0;
            }
#else
	    if (*checkForInput[0] != *checkForInput[1])
		return 0;
#endif

	    if (timers)
	    {
                int expired = 0;
		now = GetTimeInMillis();
		if ((int) (timers->expires - now) <= 0)
		    expired = 1;

		while (timers && (int) (timers->expires - now) <= 0)
		    DoTimer(timers, now, &timers);

                if (expired)
                    return 0;
	    }
	}
	else
	{
	    fd_set tmp_set;

	    if (*checkForInput[0] == *checkForInput[1]) {
	        if (timers)
	        {
                    int expired = 0;
		    now = GetTimeInMillis();
		    if ((int) (timers->expires - now) <= 0)
		        expired = 1;

		    while (timers && (int) (timers->expires - now) <= 0)
		        DoTimer(timers, now, &timers);

                    if (expired)
                        return 0;
	        }
	    }
	    if (someReady)
		XFD_ORSET(&LastSelectMask, &ClientsWithInput, &LastSelectMask);
	    if (AnyWritesPending) {
		XFD_ANDSET(&clientsWritable, &LastSelectWriteMask, &ClientsWriteBlocked);
		    if (XFD_ANYSET(&clientsWritable)) {
		    NewOutputPending = TRUE;
		    XFD_ORSET(&OutputPending, &clientsWritable, &OutputPending);
		    XFD_UNSET(&ClientsWriteBlocked, &clientsWritable);
		    if (!XFD_ANYSET(&ClientsWriteBlocked) && NumNotifyWriteFd == 0)
			AnyWritesPending = FALSE;
		}
		if (NumNotifyWriteFd != 0) {
		    XFD_ANDSET(&tmp_set, &LastSelectWriteMask, &NotifyWriteFds);
		    if (XFD_ANYSET(&tmp_set))
			someNotifyWriteReady = TRUE;
		}
	    }

	    XFD_ANDSET(&clientsReadable, &LastSelectMask, &AllClients); 
	    XFD_ANDSET(&tmp_set, &LastSelectMask, &WellKnownConnections);
	    if (XFD_ANYSET(&tmp_set))
		QueueWorkProc(EstablishNewConnections, NULL,
		              (void *)&LastSelectMask);

	    XFD_ANDSET(&tmp_set, &LastSelectMask, &NotifyReadFds);
	    if (XFD_ANYSET(&tmp_set) || someNotifyWriteReady)
	         HandleNotifyFds();

	    if (XFD_ANYSET (&clientsReadable))
		break;
#ifdef WIN32
	    /* Windows keyboard and mouse events are added to the input queue
	       in Block- and WakupHandlers. There is no device to check if  
	       data is ready. So check here if new input is available */
#if defined(NX_TRANS_SOCKET)
            if (*checkForInput[0] != *checkForInput[1])
            {
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
                fprintf(stderr, "WaitForSomething: Returning 0 because of (*checkForInput[0] != *checkForInput[1]).\n");
#endif
		return 0;
            }
#else
	    if (*checkForInput[0] != *checkForInput[1])
		return 0;
#endif
#endif
	}
    }

    nready = 0;
    if (XFD_ANYSET (&clientsReadable))
    {
#ifndef WIN32
	for (i=0; i<howmany(XFD_SETSIZE, NFDBITS); i++)
	{
	    while (clientsReadable.fds_bits[i])
	    {
		int client_index;

		curclient = ffs (clientsReadable.fds_bits[i]) - 1;
		client_index = /* raphael: modified */
			ConnectionTranslation[curclient + (i * (sizeof(fd_mask) * 8))];
#else
	fd_set savedClientsReadable;
	XFD_COPYSET(&clientsReadable, &savedClientsReadable);
	for (i = 0; i < XFD_SETCOUNT(&savedClientsReadable); i++)
	{
	    int client_priority, client_index;

	    curclient = XFD_FD(&savedClientsReadable, i);
	    client_index = GetConnectionTranslation(curclient);
#endif
	    pClientsReady[nready++] = client_index;
#ifndef WIN32
	    clientsReadable.fds_bits[i] &= ~(((fd_mask)1L) << curclient);
	}
#else
	    FD_CLR(curclient, &clientsReadable);
#endif
	}
    }
#if defined(NX_TRANS_SOCKET) && defined(NX_TRANS_DEBUG)
    fprintf(stderr, "WaitForSomething: Returning nready.\n");
#endif
    return nready;
}

#if 0
/*
 * This is not always a macro.
 */
ANYSET(FdMask *src)
{
    int i;

    for (i=0; i<mskcnt; i++)
	if (src[ i ])
	    return (TRUE);
    return (FALSE);
}
#endif


static void
DoTimer(OsTimerPtr timer, CARD32 now, OsTimerPtr *prev)
{
    CARD32 newTime;

    *prev = timer->next;
    timer->next = NULL;
    newTime = (*timer->callback)(timer, now, timer->arg);
    if (newTime)
	TimerSet(timer, 0, newTime, timer->callback, timer->arg);
}

OsTimerPtr
TimerSet(OsTimerPtr timer, int flags, CARD32 millis, 
    OsTimerCallback func, void * arg)
{
    register OsTimerPtr *prev;
    CARD32 now = GetTimeInMillis();

    if (!timer)
    {
	timer = (OsTimerPtr)malloc(sizeof(struct _OsTimerRec));
	if (!timer)
	    return NULL;
    }
    else
    {
	for (prev = &timers; *prev; prev = &(*prev)->next)
	{
	    if (*prev == timer)
	    {
		*prev = timer->next;
		if (flags & TimerForceOld)
		    (void)(*timer->callback)(timer, now, timer->arg);
		break;
	    }
	}
    }
    if (!millis)
	return timer;
    if (!(flags & TimerAbsolute))
	millis += now;
    timer->expires = millis;
    timer->callback = func;
    timer->arg = arg;
    if ((int) (millis - now) <= 0)
    {
	timer->next = NULL;
	millis = (*timer->callback)(timer, now, timer->arg);
	if (!millis)
	    return timer;
    }
    for (prev = &timers;
	 *prev && (int) ((*prev)->expires - millis) <= 0;
	 prev = &(*prev)->next)
	;
    timer->next = *prev;
    *prev = timer;
    return timer;
}

Bool
TimerForce(OsTimerPtr timer)
{
    OsTimerPtr *prev;

    for (prev = &timers; *prev; prev = &(*prev)->next)
    {
	if (*prev == timer)
	{
	    DoTimer(timer, GetTimeInMillis(), prev);
	    return TRUE;
	}
    }
    return FALSE;
}


void
TimerCancel(OsTimerPtr timer)
{
    OsTimerPtr *prev;

    if (!timer)
	return;
    for (prev = &timers; *prev; prev = &(*prev)->next)
    {
	if (*prev == timer)
	{
	    *prev = timer->next;
	    break;
	}
    }
}

void
TimerFree(OsTimerPtr timer)
{
    if (!timer)
	return;
    TimerCancel(timer);
    free(timer);
}

void
TimerCheck(void)
{
    CARD32 now = GetTimeInMillis();

    while (timers && (int) (timers->expires - now) <= 0)
	DoTimer(timers, now, &timers);
}

void
TimerInit(void)
{
    OsTimerPtr timer;

    while ((timer = timers))
    {
	timers = timer->next;
	free(timer);
    }
}

static CARD32
ScreenSaverTimeoutExpire(OsTimerPtr timer,CARD32 now,void * arg)
{
    INT32 timeout = now - lastDeviceEventTime.milliseconds;

    if (timeout < ScreenSaverTime) {
        return ScreenSaverTime - timeout;
    }

    ResetOsBuffers(); /* not ideal, but better than nothing */
    SaveScreens(SCREEN_SAVER_ON, ScreenSaverActive);

#ifdef DPMSExtension
    if (ScreenSaverInterval > 0 && DPMSPowerLevel == DPMSModeOn)
#else
    if (ScreenSaverInterval > 0)
#endif /* DPMSExtension */
        return ScreenSaverInterval;

    return 0;
}

static OsTimerPtr ScreenSaverTimer = NULL;

void
FreeScreenSaverTimer(void)
{
    if (ScreenSaverTimer) {
	TimerFree(ScreenSaverTimer);
	ScreenSaverTimer = NULL;
    }
}

void
SetScreenSaverTimer(void)
{
    if (ScreenSaverTime > 0) {
       ScreenSaverTimer = TimerSet(ScreenSaverTimer, 0, ScreenSaverTime,
                                   ScreenSaverTimeoutExpire, NULL);
    } else if (ScreenSaverTimer) {
       FreeScreenSaverTimer();
    }
}

#ifdef DPMSExtension

static OsTimerPtr DPMSStandbyTimer = NULL;
static OsTimerPtr DPMSSuspendTimer = NULL;
static OsTimerPtr DPMSOffTimer = NULL;

static CARD32
DPMSStandbyTimerExpire(OsTimerPtr timer,CARD32 now,void * arg)
{
    INT32 timeout = now - lastDeviceEventTime.milliseconds;

    if (timeout < DPMSStandbyTime) {
        return DPMSStandbyTime - timeout;
    }
    if (DPMSPowerLevel < DPMSModeStandby) {
	if (DPMSEnabled)
	    DPMSSet(DPMSModeStandby);
    }
    return DPMSStandbyTime;
}

static CARD32
DPMSSuspendTimerExpire(OsTimerPtr timer,CARD32 now,void * arg)
{
    INT32 timeout = now - lastDeviceEventTime.milliseconds;

    if (timeout < DPMSSuspendTime) {
        return DPMSSuspendTime - timeout;
    }
    if (DPMSPowerLevel < DPMSModeSuspend) {
	if (DPMSEnabled)
	    DPMSSet(DPMSModeSuspend);
    }
    return DPMSSuspendTime;
}

static CARD32
DPMSOffTimerExpire(OsTimerPtr timer,CARD32 now,void * arg)
{
    INT32 timeout = now - lastDeviceEventTime.milliseconds;

    if (timeout < DPMSOffTime) {
        return DPMSOffTime - timeout;
    }
    if (DPMSPowerLevel < DPMSModeOff) {
	if (DPMSEnabled)
	    DPMSSet(DPMSModeOff);
    }
    return DPMSOffTime;
}

void
FreeDPMSTimers(void)
{
    if (DPMSStandbyTimer) {
	TimerFree(DPMSStandbyTimer);
	DPMSStandbyTimer = NULL;
    }
    if (DPMSSuspendTimer) {
	TimerFree(DPMSSuspendTimer);
	DPMSSuspendTimer = NULL;
    }
    if (DPMSOffTimer) {
	TimerFree(DPMSOffTimer);
	DPMSOffTimer = NULL;
    }
}

void
SetDPMSTimers(void)
{
    if (!DPMSEnabled)
        return;

    DPMSStandbyTimer = TimerSet(DPMSStandbyTimer, 0, DPMSStandbyTime,
				DPMSStandbyTimerExpire, NULL);
    DPMSSuspendTimer = TimerSet(DPMSSuspendTimer, 0, DPMSSuspendTime,
				DPMSSuspendTimerExpire, NULL);
    DPMSOffTimer = TimerSet(DPMSOffTimer, 0, DPMSOffTime,
			    DPMSOffTimerExpire, NULL);
}
#endif