summaryrefslogtreecommitdiff
path: root/hw/dmx/input/dmxbackend.c
blob: b94c6d468a14688be9bab79cc704a2e35bb9ae88 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
/*
 * Copyright 2001-2003 Red Hat Inc., Durham, North Carolina.
 *
 * 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 on 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
 * NON-INFRINGEMENT.  IN NO EVENT SHALL RED HAT AND/OR THEIR 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:
 *   David H. Dawes <dawes@xfree86.org>
 *   Kevin E. Martin <kem@redhat.com>
 *   Rickard E. (Rik) Faith <faith@redhat.com>
 */

/** \file
 * These routines support taking input from devices on the backend
 * (output) displays.  \see dmxcommon.c. */

#ifdef HAVE_DMX_CONFIG_H
#include <dmx-config.h>
#endif

#define DMX_BACKEND_DEBUG 0

#include "dmxinputinit.h"
#include "dmxbackend.h"
#include "dmxcommon.h"
#include "dmxconsole.h"
#include "dmxcursor.h"
#include "dmxprop.h"
#include "dmxsync.h"
#include "dmxcb.h"              /* For dmxGlobalWidth and dmxGlobalHeight */
#include "dmxevents.h"          /* For dmxGetGlobalPosition */
#include "ChkNotMaskEv.h"

#include "inputstr.h"
#include "input.h"
#include <X11/keysym.h>
#include "mipointer.h"
#include "scrnintstr.h"
#include "windowstr.h"

/* Private area for backend devices. */
typedef struct _myPrivate {
    DMX_COMMON_PRIVATE;
    int                     myScreen;
    DMXScreenInfo           *grabbedScreen;
    
    int                     lastX, lastY;
    int                     centerX, centerY;
    int                     relative;
    int                     newscreen;
    int                     initialized;
    DevicePtr               mou, kbd;
    int                     entered;
    int                     offX, offY;
} myPrivate;

#if DMX_BACKEND_DEBUG
#define DMXDBG0(f)                   dmxLog(dmxDebug,f)
#define DMXDBG1(f,a)                 dmxLog(dmxDebug,f,a)
#define DMXDBG2(f,a,b)               dmxLog(dmxDebug,f,a,b)
#define DMXDBG3(f,a,b,c)             dmxLog(dmxDebug,f,a,b,c)
#define DMXDBG4(f,a,b,c,d)           dmxLog(dmxDebug,f,a,b,c,d)
#define DMXDBG5(f,a,b,c,d,e)         dmxLog(dmxDebug,f,a,b,c,d,e)
#define DMXDBG6(f,a,b,c,d,e,g)       dmxLog(dmxDebug,f,a,b,c,d,e,g)
#define DMXDBG7(f,a,b,c,d,e,g,h)     dmxLog(dmxDebug,f,a,b,c,d,e,g,h)
#define DMXDBG8(f,a,b,c,d,e,g,h,i)   dmxLog(dmxDebug,f,a,b,c,d,e,g,h,i)
#define DMXDBG9(f,a,b,c,d,e,g,h,i,j) dmxLog(dmxDebug,f,a,b,c,d,e,g,h,i,j)
#else
#define DMXDBG0(f)
#define DMXDBG1(f,a)
#define DMXDBG2(f,a,b)
#define DMXDBG3(f,a,b,c)
#define DMXDBG4(f,a,b,c,d)
#define DMXDBG5(f,a,b,c,d,e)
#define DMXDBG6(f,a,b,c,d,e,g)
#define DMXDBG7(f,a,b,c,d,e,g,h)
#define DMXDBG8(f,a,b,c,d,e,g,h,i)
#define DMXDBG9(f,a,b,c,d,e,g,h,i,j)
#endif

/** Create and return a private data structure. */
pointer dmxBackendCreatePrivate(DeviceIntPtr pDevice)
{
    GETDMXLOCALFROMPDEVICE;
    myPrivate *priv = calloc(1, sizeof(*priv));
    priv->dmxLocal  = dmxLocal;
    return priv;
}

/** Destroy the private data structure.  No checking is performed to
 * verify that the structure was actually created by
 * #dmxBackendCreatePrivate. */
void dmxBackendDestroyPrivate(pointer private)
{
    if (private) free(private);
}

static void *dmxBackendTestScreen(DMXScreenInfo *dmxScreen, void *closure)
{
    long target = (long)closure;

    if (dmxScreen->index == target) return dmxScreen;
    return NULL;
}

/* Return non-zero if screen and priv->myScreen are on the same physical
 * backend display (1 if they are the same screen, 2 if they are
 * different screens).  Since this is a common operation, the results
 * are cached.  The cache is invalidated if \a priv is NULL (this should
 * be done with each server generation and reconfiguration). */
static int dmxBackendSameDisplay(myPrivate *priv, long screen)
{
    static myPrivate *oldpriv  = NULL;
    static int       oldscreen = -1;
    static int       retcode   = 0;

    if (priv == oldpriv && screen == oldscreen) return retcode;
    if (!priv) {                /* Invalidate cache */
        oldpriv   = NULL;
        oldscreen = -1;
        retcode   = 0;
        return 0;
    }

    if (screen == priv->myScreen)                     retcode = 1;
    else if (screen < 0 || screen >= dmxNumScreens)   retcode = 0;
    else if (dmxPropertyIterate(priv->be,
                                dmxBackendTestScreen,
                                (void *)screen))      retcode = 2;
    else                                              retcode = 0;

    oldpriv   = priv;
    oldscreen = screen;
    return retcode;
}

static void *dmxBackendTestEvents(DMXScreenInfo *dmxScreen, void *closure)
{
    XEvent *X = (XEvent *)closure;
    
    if (XCheckNotMaskEvent(dmxScreen->beDisplay, ExposureMask, X))
        return dmxScreen;
    return NULL;
}

static void *dmxBackendTestMotionEvent(DMXScreenInfo *dmxScreen, void *closure)
{
    XEvent *X = (XEvent *)closure;

    if (XCheckTypedEvent(dmxScreen->beDisplay, MotionNotify, X))
        return dmxScreen;
    return NULL;
}

static DMXScreenInfo *dmxBackendGetEvent(myPrivate *priv, XEvent *X)
{
    DMXScreenInfo *dmxScreen;

    if ((dmxScreen = dmxPropertyIterate(priv->be, dmxBackendTestEvents, X)))
        return dmxScreen;
    return NULL;
}

static DMXScreenInfo *dmxBackendPendingMotionEvent(myPrivate *priv, int save)
{
    DMXScreenInfo *dmxScreen;
    XEvent        N;

    if ((dmxScreen = dmxPropertyIterate(priv->be,
                                        dmxBackendTestMotionEvent, &N))) {
        if (save) XPutBackEvent(dmxScreen->beDisplay, &N);
        return dmxScreen;
    }
    return NULL;
}

static void *dmxBackendTestWindow(DMXScreenInfo *dmxScreen, void *closure)
{
    Window win = (Window)(long)closure;
    if (dmxScreen->scrnWin == win) return dmxScreen;
    return NULL;
}

static DMXScreenInfo *dmxBackendFindWindow(myPrivate *priv, Window win)
{
    return dmxPropertyIterate(priv->be, dmxBackendTestWindow,
                              (void *)(long)win);
}

/* If the cursor is over a set of overlapping screens and one of those
 * screens takes backend input, then we want that particular screen to
 * be current, not one of the other ones. */
static int dmxBackendFindOverlapping(myPrivate *priv, int screen, int x, int y)
{
    DMXScreenInfo *start = &dmxScreens[screen];
    DMXScreenInfo *pt;

    if (!start->over) return screen;
    
    for (pt = start->over; /* condition at end of loop */; pt = pt->over) {
        if (pt->index == priv->myScreen
            && dmxOnScreen(x, y, &dmxScreens[pt->index])) return pt->index;
        if (pt == start) break;
    }
    return screen;
}

/* Return non-zero if \a x and \a y are off \a screen. */
static int dmxBackendOffscreen(int screen, int x, int y)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[screen];

    return (!dmxOnScreen(x, y, dmxScreen));
}

/** This routine is called from #dmxCoreMotion for each motion
 * event. #x and #y are global coordinants. */
void dmxBackendUpdatePosition(pointer private, int x, int y)
{
    GETPRIVFROMPRIVATE;
    int           screen      = miPointerGetScreen(inputInfo.pointer)->myNum;
    DMXScreenInfo *dmxScreen  = &dmxScreens[priv->myScreen];
    int           oldRelative = priv->relative;
    int           topscreen   = dmxBackendFindOverlapping(priv, screen, x, y);
    int           same        = dmxBackendSameDisplay(priv, topscreen);
    int           offscreen   = dmxBackendOffscreen(priv->myScreen, x, y);
    int           offthis     = dmxBackendOffscreen(screen, x, y);

    DMXDBG9("dmxBackendUpdatePosition(%d,%d) my=%d mi=%d rel=%d"
            " topscreen=%d same=%d offscreen=%d offthis=%d\n",
            x, y, priv->myScreen, screen, priv->relative,
            topscreen, same, offscreen, offthis);

    if (offscreen) {
        /* If the cursor is off the input screen, it should be moving
         * relative unless it is visible on a screen of the same display
         * (i.e., one that shares the mouse). */
        if (same == 2 && !offthis) {
            if (priv->relative) {
                DMXDBG0("   Off screen, but not absolute\n");
                priv->relative = 0;
            }
        } else {
            if (!priv->relative) {
                DMXDBG0("   Off screen, but not relative\n");
                priv->relative = 1;
            }
        }
    } else {
        if (topscreen != screen) {
            DMXDBG2("   Using screen %d instead of %d (from mi)\n",
                    topscreen, screen);
        }
        if (same) {
            if (priv->relative) {
                DMXDBG0("   On screen, but not absolute\n");
                priv->relative = 0;
            }
        } else {
            if (!priv->relative) {
                DMXDBG0("   Not on screen, but not relative\n");
                priv->relative = 1;
            }
        }
    }

    if (oldRelative != priv->relative) {
        DMXDBG2("   Do switch, relative=%d same=%d\n",
                priv->relative, same);
        /* Discard all pre-switch events */
        dmxSync(dmxScreen, TRUE);
        while (dmxBackendPendingMotionEvent(priv, FALSE));
        
        if (dmxInput->console && offscreen) {
            /* Our special case is a console window and a backend window
             * share a display.  In this case, the cursor is either on
             * the backend window (taking absolute input), or not (in
             * which case the cursor needs to be in the console
             * window). */
            if (priv->grabbedScreen) {
                DMXDBG2("   *** force ungrab on %s, display=%p\n",
                        priv->grabbedScreen->name,
                        priv->grabbedScreen->beDisplay);
                XUngrabPointer(priv->grabbedScreen->beDisplay, CurrentTime);
                dmxSync(priv->grabbedScreen, TRUE);
                priv->grabbedScreen = NULL;
            }
            DMXDBG0("   Capturing console\n");
            dmxConsoleCapture(dmxInput);
        } else {
            priv->newscreen = 1;
            if (priv->relative && !dmxInput->console) {
                DMXDBG5("   Hide cursor; warp from %d,%d to %d,%d on %d\n",
                        priv->lastX, priv->lastY, priv->centerX, priv->centerY,
                        priv->myScreen);
                dmxConsoleUncapture(dmxInput);
                dmxHideCursor(dmxScreen);
                priv->lastX   = priv->centerX;
                priv->lastY   = priv->centerY;
                XWarpPointer(priv->display, None, priv->window,
                             0, 0, 0, 0, priv->lastX, priv->lastY);
                dmxSync(dmxScreen, TRUE);
            } else {
                DMXDBG0("   Check cursor\n");
                dmxCheckCursor();
            }
        }
    }
}

/** Get events from the X queue on the backend servers and put the
 * events into the DMX event queue. */
void dmxBackendCollectEvents(DevicePtr pDev,
                             dmxMotionProcPtr motion,
                             dmxEnqueueProcPtr enqueue,
                             dmxCheckSpecialProcPtr checkspecial,
                             DMXBlockType block)
{
    GETPRIVFROMPDEV;
    GETDMXINPUTFROMPRIV;
    XEvent               X;
    DMXScreenInfo        *dmxScreen;
    int                  left        = 0;
    int                  entered     = priv->entered;
    int                  ignoreLeave = 0;
    int                  v[2];
    int                  retcode;

    while ((dmxScreen = dmxBackendGetEvent(priv, &X))) {
	switch (X.type) {
        case EnterNotify:
            dmxCommonSaveState(priv);
            if (entered++)
                continue;
            priv->entered = 1;
            ignoreLeave   = 1;
            DMXDBG5("dmxBackendCollectEvents: Enter %lu %d,%d; GRAB %s %p\n",
                    X.xcrossing.root, X.xcrossing.x, X.xcrossing.y,
                    dmxScreen->name, dmxScreen->beDisplay);
            XRaiseWindow(dmxScreen->beDisplay, dmxScreen->scrnWin);
            priv->grabbedScreen = dmxScreen;
            if ((retcode = XGrabPointer(dmxScreen->beDisplay,
					dmxScreen->scrnWin,
                                        True, 0, GrabModeAsync,
                                        GrabModeAsync, None, None,
                                        CurrentTime))) {
                dmxLog(dmxError,
                       "XGrabPointer failed during backend enter (%d)\n",
                       retcode);
            }
            break;
        case LeaveNotify:
            if (ignoreLeave) {
                ignoreLeave = 0;
                continue;
            }
            dmxCommonRestoreState(priv);
            if (left++)
                continue;
            DMXDBG7("dmxBackendCollectEvents: Leave %lu %d,%d %d %d %s %s\n",
                    X.xcrossing.root, X.xcrossing.x, X.xcrossing.y,
                    X.xcrossing.detail, X.xcrossing.focus,
                    priv->grabbedScreen ? "UNGRAB" : "",
                    dmxScreen->name);
            if (priv->grabbedScreen) {
                XUngrabPointer(priv->grabbedScreen->beDisplay, CurrentTime);
                dmxSync(priv->grabbedScreen, TRUE);
                priv->grabbedScreen = NULL;
            }
            break;
	case MotionNotify:
            DMXDBG9("dmxBackendCollectEvents: MotionNotify %d/%d (mi %d)"
                    " newscreen=%d: %d %d (e=%d; last=%d,%d)\n",
                    dmxScreen->index, priv->myScreen,
                    miPointerCurrentScreen()->myNum,
                    priv->newscreen,
                    X.xmotion.x, X.xmotion.y,
                    entered, priv->lastX, priv->lastY);
            if (dmxBackendPendingMotionEvent(priv, TRUE))
                continue;
            if (!(dmxScreen = dmxBackendFindWindow(priv, X.xmotion.window)))
                dmxLog(dmxFatal,
                       "   Event on non-existant window %lu\n",
                       X.xmotion.window);
            if (!priv->relative || dmxInput->console) {
                int newX = X.xmotion.x - dmxScreen->rootX;
                int newY = X.xmotion.y - dmxScreen->rootY;

                if (!priv->newscreen) {
                    int width  = dmxScreen->rootWidth;
                    int height = dmxScreen->rootHeight;
                    if (!newX)              newX = -1;
                    if (newX == width - 1)  newX = width;
                    if (!newY)              newY = -1;
                    if (newY == height - 1) newY = height;
                }
                priv->newscreen = 0;
                v[0] = dmxScreen->rootXOrigin + newX;
                v[1] = dmxScreen->rootYOrigin + newY;
                DMXDBG8("   Absolute move: %d,%d (r=%dx%d+%d+%d s=%dx%d)\n",
                        v[0], v[1],
                        priv->be->rootWidth, priv->be->rootHeight,
                        priv->be->rootX, priv->be->rootY,
                        priv->be->scrnWidth, priv->be->scrnHeight);
                motion(priv->mou, v, 0, 2, DMX_ABSOLUTE, block);
                priv->entered = 0;
            } else {
                int newX = priv->lastX - X.xmotion.x;
                int newY = priv->lastY - X.xmotion.y;
                priv->lastX = X.xmotion.x;
                priv->lastY = X.xmotion.y;
                v[0]        = newX;
                v[1]        = newY;
                DMXDBG2("   Relative move: %d, %d\n", v[0], v[1]);
                motion(priv->mou, v, 0, 2, DMX_RELATIVE, block);
            }
            if (entered && priv->relative) {
                DMXDBG4("   **** Relative %d %d instead of absolute %d %d\n",
                        v[0], v[1],
                        (dmxScreen->rootXOrigin + X.xmotion.x
                         - dmxScreen->rootX),
                        (dmxScreen->rootYOrigin + X.xmotion.y
                         - dmxScreen->rootY));
            }
	    break;

        case KeyPress:
        case KeyRelease:
            enqueue(priv->kbd, X.type, X.xkey.keycode, 0, NULL, block);
            break;
        case ButtonPress:
        case ButtonRelease:
            /* fall-through */
	default:
                                /* Pass the whole event here, because
                                 * this may be an extension event. */
            enqueue(priv->mou, X.type, X.xbutton.button, 0, &X, block);
	    break;
	}
    }
}

/** Called after input events are processed from the DMX queue.  No
 * event processing actually takes place here, but this is a convenient
 * place to update the pointer. */
void dmxBackendProcessInput(pointer private)
{
    GETPRIVFROMPRIVATE;

    DMXDBG6("dmxBackendProcessInput: myScreen=%d relative=%d"
            " last=%d,%d center=%d,%d\n",
            priv->myScreen, priv->relative,
            priv->lastX, priv->lastY,
            priv->centerX, priv->centerY);

    if (priv->relative
        && !dmxInput->console
        && (priv->lastX != priv->centerX || priv->lastY != priv->centerY)) {
        DMXDBG4("   warping pointer from last=%d,%d to center=%d,%d\n",
                priv->lastX, priv->lastY, priv->centerX, priv->centerY);
	priv->lastX   = priv->centerX;
	priv->lastY   = priv->centerY;
        XWarpPointer(priv->display, None, priv->window,
                     0, 0, 0, 0, priv->lastX, priv->lastY);
        dmxSync(&dmxScreens[priv->myScreen], TRUE);
    }
}

static void dmxBackendComputeCenter(myPrivate *priv)
{
    int centerX;
    int centerY;
    
    centerX       = priv->be->rootWidth / 2 + priv->be->rootX;
    centerY       = priv->be->rootHeight / 2 + priv->be->rootY;

    if (centerX > priv->be->rootWidth)  centerX = priv->be->rootWidth  - 1;
    if (centerY > priv->be->rootHeight) centerY = priv->be->rootHeight - 1;
    if (centerX < 1)                    centerX = 1;
    if (centerY < 1)                    centerY = 1;

    priv->centerX = centerX;
    priv->centerY = centerY;
}

static DMXScreenInfo *dmxBackendInitPrivate(DevicePtr pDev)
{
    GETPRIVFROMPDEV;
    DMXInputInfo      *dmxInput = &dmxInputs[dmxLocal->inputIdx];
    DMXScreenInfo     *dmxScreen;
    int               i;

    /* Fill in myPrivate */
    for (i = 0,dmxScreen = &dmxScreens[0]; i<dmxNumScreens; i++,dmxScreen++) {
        if (dmxPropertySameDisplay(dmxScreen, dmxInput->name)) {
            priv->display  = dmxScreen->beDisplay;
            priv->window   = dmxScreen->scrnWin;
            priv->be       = dmxScreen;
            break;
        }
    }

    if (i >= dmxNumScreens)
        dmxLog(dmxFatal,
               "%s is not an existing backend display - cannot initialize\n",
               dmxInput->name);

    return dmxScreen;
}

/** Re-initialized the backend device described by \a pDev (after a
 * reconfig). */
void dmxBackendLateReInit(DevicePtr pDev)
{
    GETPRIVFROMPDEV;
    int               x, y;

    DMXDBG1("dmxBackendLateReInit miPointerCurrentScreen() = %p\n",
            miPointerCurrentScreen());

    dmxBackendSameDisplay(NULL, 0); /* Invalidate cache */
    dmxBackendInitPrivate(pDev);
    dmxBackendComputeCenter(priv);
    dmxGetGlobalPosition(&x, &y);
    dmxInvalidateGlobalPosition(); /* To force event processing */
    dmxBackendUpdatePosition(priv, x, y);
}

/** Initialized the backend device described by \a pDev. */
void dmxBackendInit(DevicePtr pDev)
{
    GETPRIVFROMPDEV;
    DMXScreenInfo     *dmxScreen;

    dmxBackendSameDisplay(NULL, 0); /* Invalidate cache */

    if (dmxLocal->type == DMX_LOCAL_MOUSE)    priv->mou = pDev;
    if (dmxLocal->type == DMX_LOCAL_KEYBOARD) priv->kbd = pDev;
    if (priv->initialized++) return; /* Only do once for mouse/keyboard pair */

    dmxScreen = dmxBackendInitPrivate(pDev);

    /* Finish initialization using computed values or constants. */
    dmxBackendComputeCenter(priv);
    priv->eventMask          = (EnterWindowMask|LeaveWindowMask);
    priv->myScreen           = dmxScreen->index;
    priv->lastX              = priv->centerX;
    priv->lastY              = priv->centerY;
    priv->relative           = 0;
    priv->newscreen          = 0;
}

/** Get information about the backend pointer (for initialization). */
void dmxBackendMouGetInfo(DevicePtr pDev, DMXLocalInitInfoPtr info)
{
    const DMXScreenInfo *dmxScreen = dmxBackendInitPrivate(pDev);

    info->buttonClass      = 1;
    dmxCommonMouGetMap(pDev, info->map, &info->numButtons);
    info->valuatorClass    = 1;
    info->numRelAxes       = 2;
    info->minval[0]        = 0;
    info->minval[1]        = 0;
    info->maxval[0]        = dmxScreen->beWidth;
    info->maxval[1]        = dmxScreen->beHeight;
    info->res[0]           = 1;
    info->minres[0]        = 0;
    info->maxres[0]        = 1;
    info->ptrFeedbackClass = 1;
}

/** Get information about the backend keyboard (for initialization). */
void dmxBackendKbdGetInfo(DevicePtr pDev, DMXLocalInitInfoPtr info)
{
    dmxCommonKbdGetInfo(pDev, info);
    info->keyboard         = 1;
    info->keyClass         = 1;
    dmxCommonKbdGetMap(pDev, &info->keySyms, info->modMap);
    info->freemap          = 1;
    info->focusClass       = 1;
    info->kbdFeedbackClass = 1;
}

/** Process #DMXFunctionType functions.  The only function handled here
 * is to acknowledge a pending server shutdown. */
int dmxBackendFunctions(pointer private, DMXFunctionType function)
{
    switch (function) {
    case DMX_FUNCTION_TERMINATE:
        return 1;
    default:
        return 0;
    }
}