TinyX/kdrive/linux/mouse.c

/*
 *
 * Copyright © 2001 Keith Packard
 *
 * 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 name of Keith Packard not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission.  Keith Packard makes no
 * representations about the suitability of this software for any purpose.  It
 * is provided "as is" without express or implied warranty.
 *
 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL KEITH PACKARD 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.
 */

#ifdef HAVE_CONFIG_H
#include <kdrive-config.h>
#endif
#include <errno.h>
#include <termios.h>
#include <X11/X.h>
#include <X11/Xproto.h>
#include <X11/Xpoll.h>
#include "inputstr.h"
#include "scrnintstr.h"
#include "kdrive.h"

#undef DEBUG
#undef DEBUG_BYTES
#define KBUFIO_SIZE 256
#define MOUSE_TIMEOUT	100

typedef struct _kbufio {
	int fd;
	unsigned char buf[KBUFIO_SIZE];
	int avail;
	int used;
} Kbufio;

static Bool MouseWaitForReadable(int fd, int timeout)
{
	fd_set set;
	struct timeval tv, *tp;
	int n;
	CARD32 done;

	done = GetTimeInMillis() + timeout;
	for (;;) {
		FD_ZERO(&set);
		FD_SET(fd, &set);
		if (timeout == -1)
			tp = 0;
		else {
			tv.tv_sec = timeout / 1000;
			tv.tv_usec = (timeout % 1000) * 1000;
			tp = &tv;
		}
		n = select(fd + 1, &set, 0, 0, tp);
		if (n > 0)
			return TRUE;
		if (n < 0 && (errno == EAGAIN || errno == EINTR)) {
			timeout = (int)(done - GetTimeInMillis());
			if (timeout > 0)
				continue;
		}
		break;
	}
	return FALSE;
}

static int MouseReadByte(Kbufio * b, int timeout)
{
	int n;
	if (b->avail <= b->used) {
		if (timeout && !MouseWaitForReadable(b->fd, timeout)) {
#ifdef DEBUG_BYTES
			ErrorF("\tTimeout %d\n", timeout);
#endif
			return -1;
		}
		n = read(b->fd, b->buf, KBUFIO_SIZE);
		if (n <= 0)
			return -1;
		b->avail = n;
		b->used = 0;
	}
#ifdef DEBUG_BYTES
	ErrorF("\tget %02x\n", b->buf[b->used]);
#endif
	return b->buf[b->used++];
}

#if NOTUSED
static int MouseFlush(Kbufio * b, char *buf, int size)
{
	CARD32 now = GetTimeInMillis();
	CARD32 done = now + 100;
	int c;
	int n = 0;

	while ((c = MouseReadByte(b, done - now)) != -1) {
		if (buf) {
			if (n == size) {
				memmove(buf, buf + 1, size - 1);
				n--;
			}
			buf[n++] = c;
		}
		now = GetTimeInMillis();
		if ((INT32) (now - done) >= 0)
			break;
	}
	return n;
}

static int MousePeekByte(Kbufio * b, int timeout)
{
	int c;

	c = MouseReadByte(b, timeout);
	if (c != -1)
		--b->used;
	return c;
}
#endif				/* NOTUSED */

static Bool MouseWaitForWritable(int fd, int timeout)
{
	fd_set set;
	struct timeval tv, *tp;
	int n;

	FD_ZERO(&set);
	FD_SET(fd, &set);
	if (timeout == -1)
		tp = 0;
	else {
		tv.tv_sec = timeout / 1000;
		tv.tv_usec = (timeout % 1000) * 1000;
		tp = &tv;
	}
	n = select(fd + 1, 0, &set, 0, tp);
	if (n > 0)
		return TRUE;
	return FALSE;
}

static Bool MouseWriteByte(const int fd, const unsigned char c, const int timeout)
{
	int ret;

#ifdef DEBUG_BYTES
	ErrorF("\tput %02x\n", c);
#endif
	for (;;) {
		ret = write(fd, &c, 1);
		if (ret == 1)
			return TRUE;
		if (ret == 0)
			return FALSE;
		if (errno != EWOULDBLOCK)
			return FALSE;
		if (!MouseWaitForWritable(fd, timeout))
			return FALSE;
	}
}

static Bool MouseWriteBytes(const int fd, const unsigned char *c, int n,
				const int timeout)
{
	while (n--)
		if (!MouseWriteByte(fd, *c++, timeout))
			return FALSE;
	return TRUE;
}

#define MAX_MOUSE   10		/* maximum length of mouse protocol */
#define MAX_SKIP    16		/* number of error bytes before switching */
#define MAX_VALID   4		/* number of valid packets before accepting */

typedef struct _kmouseProt {
	char *name;
	 Bool(*Complete) (KdMouseInfo * mi, unsigned char *ev, int ne);
	int (*Valid) (KdMouseInfo * mi, unsigned char *ev, int ne);
	 Bool(*Parse) (KdMouseInfo * mi, unsigned char *ev, int ne);
	 Bool(*Init) (KdMouseInfo * mi);
	unsigned char headerMask, headerValid;
	unsigned char dataMask, dataValid;
	Bool tty;
	unsigned int c_iflag;
	unsigned int c_oflag;
	unsigned int c_lflag;
	unsigned int c_cflag;
	unsigned int speed;
	unsigned char *init;
	unsigned long state;
} KmouseProt;

typedef enum _kmouseStage {
	MouseBroken, MouseTesting, MouseWorking
} KmouseStage;

typedef struct _kmouse {
	Kbufio iob;
	const KmouseProt *prot;
	int i_prot;
	KmouseStage stage;	/* protocol verification stage */
	Bool tty;		/* mouse device is a tty */
	int valid;		/* sequential valid events */
	int tested;		/* bytes scanned during Testing phase */
	int invalid;		/* total invalid bytes for this protocol */
	unsigned long state;	/* private per protocol, init to prot->state */
} Kmouse;

static int mouseValid(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	const KmouseProt *prot = km->prot;
	int i;

	for (i = 0; i < ne; i++)
		if ((ev[i] & prot->headerMask) == prot->headerValid)
			break;
	if (i != 0)
		return i;
	for (i = 1; i < ne; i++)
		if ((ev[i] & prot->dataMask) != prot->dataValid)
			return -1;
	return 0;
}

static Bool threeComplete(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	return ne == 3;
}

static Bool fourComplete(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	return ne == 4;
}

static Bool fiveComplete(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	return ne == 5;
}

static Bool MouseReasonable(KdMouseInfo * mi, unsigned long flags, int dx,
			    int dy)
{
	Kmouse *km = mi->driver;

	if (km->stage == MouseWorking)
		return TRUE;
	if (dx < -50 || dx > 50) {
#ifdef DEBUG
		ErrorF("Large X %d\n", dx);
#endif
		return FALSE;
	}
	if (dy < -50 || dy > 50) {
#ifdef DEBUG
		ErrorF("Large Y %d\n", dy);
#endif
		return FALSE;
	}
	return TRUE;
}

/*
 * Standard PS/2 mouse protocol
 */
static Bool ps2Parse(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	int dx, dy, dz;
	unsigned long flags;
	unsigned long flagsrelease = 0;

	flags = KD_MOUSE_DELTA;
	if (ev[0] & 4)
		flags |= KD_BUTTON_2;
	if (ev[0] & 2)
		flags |= KD_BUTTON_3;
	if (ev[0] & 1)
		flags |= KD_BUTTON_1;

	if (ne > 3) {
		dz = (int)(signed char)ev[3];
		if (dz < 0) {
			flags |= KD_BUTTON_4;
			flagsrelease = KD_BUTTON_4;
		} else if (dz > 0) {
			flags |= KD_BUTTON_5;
			flagsrelease = KD_BUTTON_5;
		}
	}

	dx = ev[1];
	if (ev[0] & 0x10)
		dx -= 256;
	dy = ev[2];
	if (ev[0] & 0x20)
		dy -= 256;
	dy = -dy;
	if (!MouseReasonable(mi, flags, dx, dy))
		return FALSE;
	if (km->stage == MouseWorking) {
		KdEnqueueMouseEvent(mi, flags, dx, dy);
		if (flagsrelease) {
			flags &= ~flagsrelease;
			KdEnqueueMouseEvent(mi, flags, dx, dy);
		}
	}
	return TRUE;
}

static Bool ps2Init(KdMouseInfo * mi);

static const KmouseProt ps2Prot = {
	"ps/2",
	threeComplete, mouseValid, ps2Parse, ps2Init,
	0x08, 0x08, 0x00, 0x00,
	FALSE
};

static const KmouseProt imps2Prot = {
	"imps/2",
	fourComplete, mouseValid, ps2Parse, ps2Init,
	0x08, 0x08, 0x00, 0x00,
	FALSE
};

static const KmouseProt exps2Prot = {
	"exps/2",
	fourComplete, mouseValid, ps2Parse, ps2Init,
	0x08, 0x08, 0x00, 0x00,
	FALSE
};

/*
 * Once the mouse is known to speak ps/2 protocol, go and find out
 * what advanced capabilities it has and turn them on
 */

/* these extracted from FreeBSD 4.3 sys/dev/kbd/atkbdcreg.h */

/* aux device commands (sent to KBD_DATA_PORT) */
#define PSMC_SET_SCALING11      0x00e6
#define PSMC_SET_SCALING21      0x00e7
#define PSMC_SET_RESOLUTION     0x00e8
#define PSMC_SEND_DEV_STATUS    0x00e9
#define PSMC_SET_STREAM_MODE    0x00ea
#define PSMC_SEND_DEV_DATA      0x00eb
#define PSMC_SET_REMOTE_MODE    0x00f0
#define PSMC_SEND_DEV_ID        0x00f2
#define PSMC_SET_SAMPLING_RATE  0x00f3
#define PSMC_ENABLE_DEV         0x00f4
#define PSMC_DISABLE_DEV        0x00f5
#define PSMC_SET_DEFAULTS       0x00f6
#define PSMC_RESET_DEV          0x00ff

/* PSMC_SET_RESOLUTION argument */
#define PSMD_RES_LOW            0	/* typically 25ppi */
#define PSMD_RES_MEDIUM_LOW     1	/* typically 50ppi */
#define PSMD_RES_MEDIUM_HIGH    2	/* typically 100ppi (default) */
#define PSMD_RES_HIGH           3	/* typically 200ppi */
#define PSMD_MAX_RESOLUTION     PSMD_RES_HIGH

/* PSMC_SET_SAMPLING_RATE */
#define PSMD_MAX_RATE           255	/* FIXME: not sure if it's possible */

/* aux device ID */
#define PSM_MOUSE_ID            0
#define PSM_BALLPOINT_ID        2
#define PSM_INTELLI_ID          3
#define PSM_EXPLORER_ID         4
#define PSM_4DMOUSE_ID          6
#define PSM_4DPLUS_ID           8

static const unsigned char ps2_init[] = {
	PSMC_ENABLE_DEV,
	0,
};

#define NINIT_PS2   1

static const unsigned char wheel_3button_init[] = {
	PSMC_SET_SAMPLING_RATE, 200,
	PSMC_SET_SAMPLING_RATE, 100,
	PSMC_SET_SAMPLING_RATE, 80,
	PSMC_SEND_DEV_ID,
	0,
};

#define NINIT_IMPS2 4

static const unsigned char wheel_5button_init[] = {
	PSMC_SET_SAMPLING_RATE, 200,
	PSMC_SET_SAMPLING_RATE, 100,
	PSMC_SET_SAMPLING_RATE, 80,
	PSMC_SET_SAMPLING_RATE, 200,
	PSMC_SET_SAMPLING_RATE, 200,
	PSMC_SET_SAMPLING_RATE, 80,
	PSMC_SEND_DEV_ID,
	0
};

#define NINIT_EXPS2 7

static const unsigned char intelli_init[] = {
	PSMC_SET_SAMPLING_RATE, 200,
	PSMC_SET_SAMPLING_RATE, 100,
	PSMC_SET_SAMPLING_RATE, 80,
	0
};

#define NINIT_INTELLI	3

static int ps2SkipInit(KdMouseInfo * const mi, int ninit, const Bool ret_next)
{
	Kmouse * const km = mi->driver;
	int c = -1;
	Bool waiting;

	waiting = FALSE;
	while (ninit || ret_next) {
		c = MouseReadByte(&km->iob, 1); // Minimum timeout like in xf86-input-mouse
		if (c == -1)
			break;
		/* look for ACK */
		if (c == 0xfa) {
			ninit--;
			if (ret_next)
				waiting = TRUE;
		}
		/* look for packet start -- not the response */
		else if ((c & 0x08) == 0x08)
			waiting = FALSE;
		else if (waiting)
			break;
	}
	return c;
}

static Bool ps2Init(KdMouseInfo * mi)
{
	Kmouse *km = mi->driver;
	int id;
	const unsigned char *init;
	int ninit;

	/* Send Intellimouse initialization sequence */
	MouseWriteBytes(km->iob.fd, intelli_init, strlen((char *)intelli_init),
			100);
	/*
	 * Send ID command
	 */
	if (!MouseWriteByte(km->iob.fd, PSMC_SEND_DEV_ID, 100))
		return FALSE;
	id = ps2SkipInit(mi, 0, TRUE);
	switch (id) {
	case 3:
		init = wheel_3button_init;
		ninit = NINIT_IMPS2;
		km->prot = &imps2Prot;
		break;
	case 4:
		init = wheel_5button_init;
		ninit = NINIT_EXPS2;
		km->prot = &exps2Prot;
		break;
	default:
		init = ps2_init;
		ninit = NINIT_PS2;
		km->prot = &ps2Prot;
		break;
	}
	if (init)
		MouseWriteBytes(km->iob.fd, init, strlen((char *)init), 100);
	/*
	 * Flush out the available data to eliminate responses to the
	 * initialization string.  Make sure any partial event is
	 * skipped
	 */
	(void)ps2SkipInit(mi, ninit, FALSE);
	return TRUE;
}

static Bool busParse(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	int dx, dy;
	unsigned long flags;

	flags = KD_MOUSE_DELTA;
	dx = (signed char)ev[1];
	dy = -(signed char)ev[2];
	if ((ev[0] & 4) == 0)
		flags |= KD_BUTTON_1;
	if ((ev[0] & 2) == 0)
		flags |= KD_BUTTON_2;
	if ((ev[0] & 1) == 0)
		flags |= KD_BUTTON_3;
	if (!MouseReasonable(mi, flags, dx, dy))
		return FALSE;
	if (km->stage == MouseWorking)
		KdEnqueueMouseEvent(mi, flags, dx, dy);
	return TRUE;
}

static const KmouseProt busProt = {
	"bus",
	threeComplete, mouseValid, busParse, 0,
	0xf8, 0x00, 0x00, 0x00,
	FALSE
};

/*
 * Standard MS serial protocol, three bytes
 */

static Bool msParse(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	int dx, dy;
	unsigned long flags;

	flags = KD_MOUSE_DELTA;

	if (ev[0] & 0x20)
		flags |= KD_BUTTON_1;
	if (ev[0] & 0x10)
		flags |= KD_BUTTON_3;

	dx = (signed char)(((ev[0] & 0x03) << 6) | (ev[1] & 0x3F));
	dy = (signed char)(((ev[0] & 0x0C) << 4) | (ev[2] & 0x3F));
	if (!MouseReasonable(mi, flags, dx, dy))
		return FALSE;
	if (km->stage == MouseWorking)
		KdEnqueueMouseEvent(mi, flags, dx, dy);
	return TRUE;
}

static const KmouseProt msProt = {
	"ms",
	threeComplete, mouseValid, msParse, 0,
	0xc0, 0x40, 0xc0, 0x00,
	TRUE,
	IGNPAR,
	0,
	0,
	CS7 | CSTOPB | CREAD | CLOCAL,
	B1200,
};

/*
 * Logitech mice send 3 or 4 bytes, the only way to tell is to look at the
 * first byte of a synchronized protocol stream and see if it's got
 * any bits turned on that can't occur in that fourth byte
 */
static Bool logiComplete(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;

	if ((ev[0] & 0x40) == 0x40)
		return ne == 3;
	if (km->stage != MouseBroken && (ev[0] & ~0x23) == 0)
		return ne == 1;
	return FALSE;
}

static int logiValid(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	const KmouseProt *prot = km->prot;
	int i;

	for (i = 0; i < ne; i++) {
		if ((ev[i] & 0x40) == 0x40)
			break;
		if (km->stage != MouseBroken && (ev[i] & ~0x23) == 0)
			break;
	}
	if (i != 0)
		return i;
	for (i = 1; i < ne; i++)
		if ((ev[i] & prot->dataMask) != prot->dataValid)
			return -1;
	return 0;
}

static Bool logiParse(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	int dx, dy;
	unsigned long flags;

	flags = KD_MOUSE_DELTA;

	if (ne == 3) {
		if (ev[0] & 0x20)
			flags |= KD_BUTTON_1;
		if (ev[0] & 0x10)
			flags |= KD_BUTTON_3;

		dx = (signed char)(((ev[0] & 0x03) << 6) | (ev[1] & 0x3F));
		dy = (signed char)(((ev[0] & 0x0C) << 4) | (ev[2] & 0x3F));
		flags |= km->state & KD_BUTTON_2;
	} else {
		if (ev[0] & 0x20)
			flags |= KD_BUTTON_2;
		dx = 0;
		dy = 0;
		flags |= km->state & (KD_BUTTON_1 | KD_BUTTON_3);
	}

	if (!MouseReasonable(mi, flags, dx, dy))
		return FALSE;
	if (km->stage == MouseWorking)
		KdEnqueueMouseEvent(mi, flags, dx, dy);
	return TRUE;
}

static const KmouseProt logiProt = {
	"logitech",
	logiComplete, logiValid, logiParse, 0,
	0xc0, 0x40, 0xc0, 0x00,
	TRUE,
	IGNPAR,
	0,
	0,
	CS7 | CSTOPB | CREAD | CLOCAL,
	B1200,
};

/*
 * Mouse systems protocol, 5 bytes
 */
static Bool mscParse(KdMouseInfo * mi, unsigned char *ev, int ne)
{
	Kmouse *km = mi->driver;
	int dx, dy;
	unsigned long flags;

	flags = KD_MOUSE_DELTA;

	if (!(ev[0] & 0x4))
		flags |= KD_BUTTON_1;
	if (!(ev[0] & 0x2))
		flags |= KD_BUTTON_2;
	if (!(ev[0] & 0x1))
		flags |= KD_BUTTON_3;
	dx = (signed char)(ev[1]) + (signed char)(ev[3]);
	dy = -((signed char)(ev[2]) + (signed char)(ev[4]));

	if (!MouseReasonable(mi, flags, dx, dy))
		return FALSE;
	if (km->stage == MouseWorking)
		KdEnqueueMouseEvent(mi, flags, dx, dy);
	return TRUE;
}

static const KmouseProt mscProt = {
	"msc",
	fiveComplete, mouseValid, mscParse, 0,
	0xf8, 0x80, 0x00, 0x00,
	TRUE,
	IGNPAR,
	0,
	0,
	CS8 | CSTOPB | CREAD | CLOCAL,
	B1200,
};

/*
 * Use logitech before ms -- they're the same except that
 * logitech sometimes has a fourth byte
 */
static const KmouseProt *kmouseProts[] = {
	&ps2Prot, &imps2Prot, &exps2Prot, &busProt, &logiProt, &msProt,
	    &mscProt,
};

#define NUM_PROT    (sizeof (kmouseProts) / sizeof (kmouseProts[0]))

static void MouseInitProtocol(Kmouse * km)
{
	int ret;
	struct termios t;

	if (km->prot->tty) {
		ret = tcgetattr(km->iob.fd, &t);

		if (ret >= 0) {
			t.c_iflag = km->prot->c_iflag;
			t.c_oflag = km->prot->c_oflag;
			t.c_lflag = km->prot->c_lflag;
			t.c_cflag = km->prot->c_cflag;
			cfsetispeed(&t, km->prot->speed);
			cfsetospeed(&t, km->prot->speed);
			tcsetattr(km->iob.fd, TCSANOW, &t);
		}
	}
	km->stage = MouseBroken;
	km->valid = 0;
	km->tested = 0;
	km->invalid = 0;
	km->state = km->prot->state;
}

static void MouseFirstProtocol(Kmouse * km, char *prot)
{
	if (prot) {
		for (km->i_prot = 0; km->i_prot < NUM_PROT; km->i_prot++)
			if (!strcmp(prot, kmouseProts[km->i_prot]->name))
				break;
		if (km->i_prot == NUM_PROT) {
			int i;
			ErrorF("Unknown mouse protocol \"%s\". Pick one of:",
			       prot);
			for (i = 0; i < NUM_PROT; i++)
				ErrorF(" %s", kmouseProts[i]->name);
			ErrorF("\n");
		} else {
			km->prot = kmouseProts[km->i_prot];
			if (km->tty && !km->prot->tty)
				ErrorF
				    ("Mouse device is serial port, protocol %s is not serial protocol\n",
				     prot);
			else if (!km->tty && km->prot->tty)
				ErrorF
				    ("Mouse device is not serial port, protocol %s is serial protocol\n",
				     prot);
		}
	}
	if (!km->prot) {
		for (km->i_prot = 0; kmouseProts[km->i_prot]->tty != km->tty;
		     km->i_prot++) ;
		km->prot = kmouseProts[km->i_prot];
	}
	MouseInitProtocol(km);
}

static void MouseNextProtocol(Kmouse * km)
{
	do {
		if (!km->prot)
			km->i_prot = 0;
		else if (++km->i_prot == NUM_PROT)
			km->i_prot = 0;
		km->prot = kmouseProts[km->i_prot];
	} while (km->prot->tty != km->tty);
	MouseInitProtocol(km);
	ErrorF("Switching to mouse protocol \"%s\"\n", km->prot->name);
}

static void MouseRead(int mousePort, void *closure)
{
	KdMouseInfo *mi = closure;
	Kmouse *km = mi->driver;
	unsigned char event[MAX_MOUSE];
	int ne;
	int c;
	int i;
	int timeout;

	timeout = 0;
	ne = 0;
	for (;;) {
		c = MouseReadByte(&km->iob, timeout);
		if (c == -1) {
			if (ne) {
				km->invalid += ne + km->tested;
				km->valid = 0;
				km->tested = 0;
				km->stage = MouseBroken;
			}
			break;
		}
		event[ne++] = c;
		i = (*km->prot->Valid) (mi, event, ne);
		if (i != 0) {
#ifdef DEBUG
			ErrorF("Mouse protocol %s broken %d of %d bytes bad\n",
			       km->prot->name, i > 0 ? i : ne, ne);
#endif
			if (i > 0 && i < ne) {
				ne -= i;
				memmove(event, event + i, ne);
			} else {
				i = ne;
				ne = 0;
			}
			km->invalid += i + km->tested;
			km->valid = 0;
			km->tested = 0;
			if (km->stage == MouseWorking)
				km->i_prot--;
			km->stage = MouseBroken;
			if (km->invalid > MAX_SKIP) {
				MouseNextProtocol(km);
				ne = 0;
			}
			timeout = 0;
		} else {
			if ((*km->prot->Complete) (mi, event, ne)) {
				if ((*km->prot->Parse) (mi, event, ne)) {
					switch (km->stage) {
					case MouseBroken:
#ifdef DEBUG
						ErrorF
						    ("Mouse protocol %s seems OK\n",
						     km->prot->name);
#endif
						/* do not zero invalid to accumulate invalid bytes */
						km->valid = 0;
						km->tested = 0;
						km->stage = MouseTesting;
						/* fall through ... */
					case MouseTesting:
						km->valid++;
						km->tested += ne;
						if (km->valid > MAX_VALID) {
#ifdef DEBUG
							ErrorF
							    ("Mouse protocol %s working\n",
							     km->prot->name);
#endif
							km->stage =
							    MouseWorking;
							km->invalid = 0;
							km->tested = 0;
							km->valid = 0;
							if (km->prot->Init
							    && !(*km->prot->
								 Init) (mi))
								km->stage =
								    MouseBroken;
						}
						break;
					case MouseWorking:
						break;
					}
				} else {
					km->invalid += ne + km->tested;
					km->valid = 0;
					km->tested = 0;
					km->stage = MouseBroken;
				}
				ne = 0;
				timeout = 0;
			} else
				timeout = MOUSE_TIMEOUT;
		}
	}
}

static int MouseInputType;

const char * const kdefaultMouse[] = {
	"/dev/mouse",
	"/dev/psaux",
	"/dev/input/mice",
	"/dev/adbmouse",
	"/dev/ttyS0",
	"/dev/ttyS1",
};

#define NUM_DEFAULT_MOUSE    (sizeof (kdefaultMouse) / sizeof (kdefaultMouse[0]))

static Bool MouseInit(void)
{
	int i;
	int fd = -1;
	Kmouse *km;
	KdMouseInfo *mi, *next;
	int n = 0;

	if (!MouseInputType)
		MouseInputType = KdAllocInputType();

	for (mi = kdMouseInfo; mi; mi = next) {
		next = mi->next;
		if (mi->inputType)
			continue;
		if (!mi->name) {
			for (i = 0; i < NUM_DEFAULT_MOUSE; i++) {
				fd = open(kdefaultMouse[i], 2);
				if (fd >= 0) {
					mi->name = strdup(kdefaultMouse[i]);
					break;
				}
			}
		} else
			fd = open(mi->name, 2);

		if (fd >= 0) {
			km = malloc(sizeof(Kmouse));
			if (km) {
				km->iob.fd = fd;
				km->iob.avail = km->iob.used = 0;
				km->prot = 0;
				km->i_prot = 0;
				km->tty = isatty(fd);
				mi->driver = km;
				mi->inputType = MouseInputType;
				MouseFirstProtocol(km, mi->prot);
				if (KdRegisterFd
				    (MouseInputType, fd, MouseRead, (void *)mi))
					n++;
			} else
				close(fd);
		}
	}
	return TRUE;
}

static void MouseFini(void)
{
	KdMouseInfo *mi;

	KdUnregisterFds(MouseInputType, TRUE);
	for (mi = kdMouseInfo; mi; mi = mi->next) {
		if (mi->inputType == MouseInputType) {
			free(mi->driver);
			mi->driver = 0;
			mi->inputType = 0;
		}
	}
}

const KdMouseFuncs LinuxMouseFuncs = {
	MouseInit,
	MouseFini,
};