NetBSD/sys/arch/alpha/isa/pckbd.c

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/* $NetBSD: pckbd.c,v 1.1 1995/08/03 00:48:25 cgd Exp $ */
/*-
* Copyright (c) 1993, 1994, 1995 Charles Hannum. All rights reserved.
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz and Don Ahn.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)pccons.c 5.11 (Berkeley) 5/21/91
*/
/*
* code to work keyboard & display for PC-style console
*/
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/ioctl.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <machine/cpu.h>
#include <machine/pio.h>
#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>
#include <alpha/isa/pckbdreg.h>
static volatile u_char ack, nak; /* Don't ask. */
static u_char async, kernel, polling; /* Really, you don't want to know. */
static u_char lock_state = 0x00, /* all off */
old_lock_state = 0xff,
typematic_rate = 0xff, /* don't update until set by user */
old_typematic_rate = 0xff;
struct pckbd_softc {
struct device sc_dev;
void *sc_ih;
};
int pckbdprobe __P((struct device *, void *, void *));
void pckbdattach __P((struct device *, struct device *, void *));
int pckbdintr __P((void *));
struct cfdriver pckbdcd = {
NULL, "pckbd", pckbdprobe, pckbdattach, DV_DULL,
sizeof(struct pckbd_softc)
};
char *sget __P((void));
int pccngetc __P((void *));
void pccnpollc __P((void *, int));
/*
* DANGER WIL ROBINSON -- the values of SCROLL, NUM, CAPS, and ALT are
* important.
*/
#define SCROLL 0x0001 /* stop output */
#define NUM 0x0002 /* numeric shift cursors vs. numeric */
#define CAPS 0x0004 /* caps shift -- swaps case of letter */
#define SHIFT 0x0008 /* keyboard shift */
#define CTL 0x0010 /* control shift -- allows ctl function */
#define ASCII 0x0020 /* ascii code for this key */
#define ALT 0x0080 /* alternate shift -- alternate chars */
#define FUNC 0x0100 /* function key */
#define KP 0x0200 /* Keypad keys */
#define NONE 0x0400 /* no function */
#define KBD_DELAY \
{ u_char x = inb(0x84); } \
{ u_char x = inb(0x84); } \
{ u_char x = inb(0x84); } \
{ u_char x = inb(0x84); }
static inline int
kbd_wait_output()
{
u_int i;
for (i = 100000; i; i--)
if ((inb(KBSTATP) & KBS_IBF) == 0) {
KBD_DELAY;
return 1;
}
return 0;
}
static inline int
kbd_wait_input()
{
u_int i;
for (i = 100000; i; i--)
if ((inb(KBSTATP) & KBS_DIB) != 0) {
KBD_DELAY;
return 1;
}
return 0;
}
static inline void
kbd_flush_input()
{
u_int i;
for (i = 10; i; i--) {
if ((inb(KBSTATP) & KBS_DIB) == 0)
return;
KBD_DELAY;
(void) inb(KBDATAP);
}
}
#if 1
/*
* Get the current command byte.
*/
static u_char
kbc_get8042cmd()
{
if (!kbd_wait_output())
return -1;
outb(KBCMDP, K_RDCMDBYTE);
if (!kbd_wait_input())
return -1;
return inb(KBDATAP);
}
#endif
/*
* Pass command byte to keyboard controller (8042).
*/
static int
kbc_put8042cmd(val)
u_char val;
{
if (!kbd_wait_output())
return 0;
outb(KBCMDP, K_LDCMDBYTE);
if (!kbd_wait_output())
return 0;
outb(KBOUTP, val);
return 1;
}
/*
* Pass command to keyboard itself
*/
int
kbd_cmd(val, polling)
u_char val;
u_char polling;
{
u_int retries = 3;
register u_int i;
do {
if (!kbd_wait_output())
return 0;
ack = nak = 0;
outb(KBOUTP, val);
if (polling)
for (i = 100000; i; i--) {
if (inb(KBSTATP) & KBS_DIB) {
register u_char c;
KBD_DELAY;
c = inb(KBDATAP);
if (c == KBR_ACK || c == KBR_ECHO) {
ack = 1;
return 1;
}
if (c == KBR_RESEND) {
nak = 1;
break;
}
#ifdef DIAGNOSTIC
printf("kbd_cmd: input char %x lost\n", c);
#endif
}
}
else
for (i = 100000; i; i--) {
(void) inb(KBSTATP);
if (ack)
return 1;
if (nak)
break;
}
if (!nak)
return 0;
} while (--retries);
return 0;
}
/*
* these are both bad jokes
*/
int
pckbdprobe(parent, match, aux)
struct device *parent;
void *match, *aux;
{
struct isa_attach_args *ia = aux;
u_int i;
/* Enable interrupts and keyboard, etc. */
if (!kbc_put8042cmd(CMDBYTE)) {
printf("pcprobe: command error\n");
return 0;
}
#if 1
/* Flush any garbage. */
kbd_flush_input();
/* Reset the keyboard. */
if (!kbd_cmd(KBC_RESET, 1)) {
printf("pcprobe: reset error %d\n", 1);
goto lose;
}
for (i = 600000; i; i--)
if ((inb(KBSTATP) & KBS_DIB) != 0) {
KBD_DELAY;
break;
}
if (i == 0 || inb(KBDATAP) != KBR_RSTDONE) {
printf("pcprobe: reset error %d\n", 2);
goto lose;
}
/*
* Some keyboards seem to leave a second ack byte after the reset.
* This is kind of stupid, but we account for them anyway by just
* flushing the buffer.
*/
kbd_flush_input();
/* Just to be sure. */
if (!kbd_cmd(KBC_ENABLE, 1)) {
printf("pcprobe: reset error %d\n", 3);
goto lose;
}
/*
* Some keyboard/8042 combinations do not seem to work if the keyboard
* is set to table 1; in fact, it would appear that some keyboards just
* ignore the command altogether. So by default, we use the AT scan
* codes and have the 8042 translate them. Unfortunately, this is
* known to not work on some PS/2 machines. We try desparately to deal
* with this by checking the (lack of a) translate bit in the 8042 and
* attempting to set the keyboard to XT mode. If this all fails, well,
* tough luck.
*
* XXX It would perhaps be a better choice to just use AT scan codes
* and not bother with this.
*/
if (kbc_get8042cmd() & KC8_TRANS) {
/* The 8042 is translating for us; use AT codes. */
if (!kbd_cmd(KBC_SETTABLE, 1) || !kbd_cmd(2, 1)) {
printf("pcprobe: reset error %d\n", 4);
goto lose;
}
} else {
/* Stupid 8042; set keyboard to XT codes. */
if (!kbd_cmd(KBC_SETTABLE, 1) || !kbd_cmd(1, 1)) {
printf("pcprobe: reset error %d\n", 5);
goto lose;
}
}
lose:
/*
* Technically, we should probably fail the probe. But we'll be nice
* and allow keyboard-less machines to boot with the console.
*/
#endif
ia->ia_iosize = 16;
ia->ia_msize = 0;
return 1;
}
void
pckbdattach(parent, self, aux)
struct device *parent, *self;
void *aux;
{
struct pckbd_softc *sc = (void *)self;
struct isa_attach_args *ia = aux;
printf("\n");
sc->sc_ih = isa_intr_establish(ia->ia_irq, ISA_IST_EDGE, ISA_IPL_TTY,
pckbdintr, sc);
wscattach_input(self, self, pccngetc, pccnpollc);
}
/*
* Got a console receive interrupt -
* the console processor wants to give us a character.
* Catch the character, and see who it goes to.
*/
int
pckbdintr(arg)
void *arg;
{
struct pckbd_softc *sc = arg;
u_char *cp;
if ((inb(KBSTATP) & KBS_DIB) == 0)
return 0;
if (polling)
return 1;
do {
cp = sget();
if (cp)
wscons_kbdinput(cp);
} while (inb(KBSTATP) & KBS_DIB);
return 1;
}
void
do_async_update(poll)
u_char poll;
{
int pos;
static int old_pos = -1;
async = 0;
if (lock_state != old_lock_state) {
old_lock_state = lock_state;
if (!kbd_cmd(KBC_MODEIND, poll) ||
!kbd_cmd(lock_state, poll)) {
printf("pc: timeout updating leds\n");
(void) kbd_cmd(KBC_ENABLE, poll);
}
}
if (typematic_rate != old_typematic_rate) {
old_typematic_rate = typematic_rate;
if (!kbd_cmd(KBC_TYPEMATIC, poll) ||
!kbd_cmd(typematic_rate, poll)) {
printf("pc: timeout updating typematic rate\n");
(void) kbd_cmd(KBC_ENABLE, poll);
}
}
}
void
async_update()
{
if (kernel || polling) {
if (async)
untimeout(do_async_update, NULL);
do_async_update(1);
} else {
if (async)
return;
async = 1;
timeout(do_async_update, NULL, 1);
}
}
#if 0
int
pcioctl(dev, cmd, data, flag, p)
dev_t dev;
u_long cmd;
caddr_t data;
int flag;
struct proc *p;
{
struct pc_softc *sc = pccd.cd_devs[PCUNIT(dev)];
int error;
error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
if (error >= 0)
return error;
error = ttioctl(tp, cmd, data, flag, p);
if (error >= 0)
return error;
switch (cmd) {
case CONSOLE_X_MODE_ON:
pc_xmode_on();
return 0;
case CONSOLE_X_MODE_OFF:
pc_xmode_off();
return 0;
case CONSOLE_X_BELL:
/*
* If set, data is a pointer to a length 2 array of
* integers. data[0] is the pitch in Hz and data[1]
* is the duration in msec.
*/
if (data)
sysbeep(((int*)data)[0],
(((int*)data)[1] * hz) / 1000);
else
sysbeep(BEEP_FREQ, BEEP_TIME);
return 0;
case CONSOLE_SET_TYPEMATIC_RATE: {
u_char rate;
if (!data)
return EINVAL;
rate = *((u_char *)data);
/*
* Check that it isn't too big (which would cause it to be
* confused with a command).
*/
if (rate & 0x80)
return EINVAL;
typematic_rate = rate;
async_update();
return 0;
}
default:
return ENOTTY;
}
#ifdef DIAGNOSTIC
panic("pcioctl: impossible");
#endif
}
#endif
#define CODE_SIZE 4 /* Use a max of 4 for now... */
typedef struct {
u_short type;
char unshift[CODE_SIZE];
char shift[CODE_SIZE];
char ctl[CODE_SIZE];
} Scan_def;
static Scan_def scan_codes[] = {
NONE, "", "", "", /* 0 unused */
ASCII, "\033", "\033", "\033", /* 1 ESCape */
ASCII, "1", "!", "!", /* 2 1 */
ASCII, "2", "@", "\000", /* 3 2 */
ASCII, "3", "#", "#", /* 4 3 */
ASCII, "4", "$", "$", /* 5 4 */
ASCII, "5", "%", "%", /* 6 5 */
ASCII, "6", "^", "\036", /* 7 6 */
ASCII, "7", "&", "&", /* 8 7 */
ASCII, "8", "*", "\010", /* 9 8 */
ASCII, "9", "(", "(", /* 10 9 */
ASCII, "0", ")", ")", /* 11 0 */
ASCII, "-", "_", "\037", /* 12 - */
ASCII, "=", "+", "+", /* 13 = */
ASCII, "\177", "\177", "\010", /* 14 backspace */
ASCII, "\t", "\177\t", "\t", /* 15 tab */
ASCII, "q", "Q", "\021", /* 16 q */
ASCII, "w", "W", "\027", /* 17 w */
ASCII, "e", "E", "\005", /* 18 e */
ASCII, "r", "R", "\022", /* 19 r */
ASCII, "t", "T", "\024", /* 20 t */
ASCII, "y", "Y", "\031", /* 21 y */
ASCII, "u", "U", "\025", /* 22 u */
ASCII, "i", "I", "\011", /* 23 i */
ASCII, "o", "O", "\017", /* 24 o */
ASCII, "p", "P", "\020", /* 25 p */
ASCII, "[", "{", "\033", /* 26 [ */
ASCII, "]", "}", "\035", /* 27 ] */
ASCII, "\r", "\r", "\n", /* 28 return */
CTL, "", "", "", /* 29 control */
ASCII, "a", "A", "\001", /* 30 a */
ASCII, "s", "S", "\023", /* 31 s */
ASCII, "d", "D", "\004", /* 32 d */
ASCII, "f", "F", "\006", /* 33 f */
ASCII, "g", "G", "\007", /* 34 g */
ASCII, "h", "H", "\010", /* 35 h */
ASCII, "j", "J", "\n", /* 36 j */
ASCII, "k", "K", "\013", /* 37 k */
ASCII, "l", "L", "\014", /* 38 l */
ASCII, ";", ":", ";", /* 39 ; */
ASCII, "'", "\"", "'", /* 40 ' */
ASCII, "`", "~", "`", /* 41 ` */
SHIFT, "", "", "", /* 42 shift */
ASCII, "\\", "|", "\034", /* 43 \ */
ASCII, "z", "Z", "\032", /* 44 z */
ASCII, "x", "X", "\030", /* 45 x */
ASCII, "c", "C", "\003", /* 46 c */
ASCII, "v", "V", "\026", /* 47 v */
ASCII, "b", "B", "\002", /* 48 b */
ASCII, "n", "N", "\016", /* 49 n */
ASCII, "m", "M", "\r", /* 50 m */
ASCII, ",", "<", "<", /* 51 , */
ASCII, ".", ">", ">", /* 52 . */
ASCII, "/", "?", "\037", /* 53 / */
SHIFT, "", "", "", /* 54 shift */
KP, "*", "*", "*", /* 55 kp * */
ALT, "", "", "", /* 56 alt */
ASCII, " ", " ", "\000", /* 57 space */
CAPS, "", "", "", /* 58 caps */
FUNC, "\033[M", "\033[Y", "\033[k", /* 59 f1 */
FUNC, "\033[N", "\033[Z", "\033[l", /* 60 f2 */
FUNC, "\033[O", "\033[a", "\033[m", /* 61 f3 */
FUNC, "\033[P", "\033[b", "\033[n", /* 62 f4 */
FUNC, "\033[Q", "\033[c", "\033[o", /* 63 f5 */
FUNC, "\033[R", "\033[d", "\033[p", /* 64 f6 */
FUNC, "\033[S", "\033[e", "\033[q", /* 65 f7 */
FUNC, "\033[T", "\033[f", "\033[r", /* 66 f8 */
FUNC, "\033[U", "\033[g", "\033[s", /* 67 f9 */
FUNC, "\033[V", "\033[h", "\033[t", /* 68 f10 */
NUM, "", "", "", /* 69 num lock */
SCROLL, "", "", "", /* 70 scroll lock */
KP, "7", "\033[H", "7", /* 71 kp 7 */
KP, "8", "\033[A", "8", /* 72 kp 8 */
KP, "9", "\033[I", "9", /* 73 kp 9 */
KP, "-", "-", "-", /* 74 kp - */
KP, "4", "\033[D", "4", /* 75 kp 4 */
KP, "5", "\033[E", "5", /* 76 kp 5 */
KP, "6", "\033[C", "6", /* 77 kp 6 */
KP, "+", "+", "+", /* 78 kp + */
KP, "1", "\033[F", "1", /* 79 kp 1 */
KP, "2", "\033[B", "2", /* 80 kp 2 */
KP, "3", "\033[G", "3", /* 81 kp 3 */
KP, "0", "\033[L", "0", /* 82 kp 0 */
KP, ".", "\177", ".", /* 83 kp . */
NONE, "", "", "", /* 84 0 */
NONE, "100", "", "", /* 85 0 */
NONE, "101", "", "", /* 86 0 */
FUNC, "\033[W", "\033[i", "\033[u", /* 87 f11 */
FUNC, "\033[X", "\033[j", "\033[v", /* 88 f12 */
NONE, "102", "", "", /* 89 0 */
NONE, "103", "", "", /* 90 0 */
NONE, "", "", "", /* 91 0 */
NONE, "", "", "", /* 92 0 */
NONE, "", "", "", /* 93 0 */
NONE, "", "", "", /* 94 0 */
NONE, "", "", "", /* 95 0 */
NONE, "", "", "", /* 96 0 */
NONE, "", "", "", /* 97 0 */
NONE, "", "", "", /* 98 0 */
NONE, "", "", "", /* 99 0 */
NONE, "", "", "", /* 100 */
NONE, "", "", "", /* 101 */
NONE, "", "", "", /* 102 */
NONE, "", "", "", /* 103 */
NONE, "", "", "", /* 104 */
NONE, "", "", "", /* 105 */
NONE, "", "", "", /* 106 */
NONE, "", "", "", /* 107 */
NONE, "", "", "", /* 108 */
NONE, "", "", "", /* 109 */
NONE, "", "", "", /* 110 */
NONE, "", "", "", /* 111 */
NONE, "", "", "", /* 112 */
NONE, "", "", "", /* 113 */
NONE, "", "", "", /* 114 */
NONE, "", "", "", /* 115 */
NONE, "", "", "", /* 116 */
NONE, "", "", "", /* 117 */
NONE, "", "", "", /* 118 */
NONE, "", "", "", /* 119 */
NONE, "", "", "", /* 120 */
NONE, "", "", "", /* 121 */
NONE, "", "", "", /* 122 */
NONE, "", "", "", /* 123 */
NONE, "", "", "", /* 124 */
NONE, "", "", "", /* 125 */
NONE, "", "", "", /* 126 */
NONE, "", "", "", /* 127 */
};
/*
* Get characters from the keyboard. If none are present, return NULL.
*/
char *
sget()
{
u_char dt;
static u_char extended = 0, shift_state = 0;
static u_char capchar[2];
top:
KBD_DELAY;
dt = inb(KBDATAP);
switch (dt) {
case KBR_ACK:
ack = 1;
goto loop;
case KBR_RESEND:
nak = 1;
goto loop;
}
#if 0
if (pc_xmode > 0) {
#if defined(DDB) && defined(XSERVER_DDB)
/* F12 enters the debugger while in X mode */
if (dt == 88)
Debugger();
#endif
capchar[0] = dt;
capchar[1] = 0;
/*
* Check for locking keys.
*
* XXX Setting the LEDs this way is a bit bogus. What if the
* keyboard has been remapped in X?
*/
switch (scan_codes[dt & 0x7f].type) {
case NUM:
if (dt & 0x80) {
shift_state &= ~NUM;
break;
}
if (shift_state & NUM)
break;
shift_state |= NUM;
lock_state ^= NUM;
async_update();
break;
case CAPS:
if (dt & 0x80) {
shift_state &= ~CAPS;
break;
}
if (shift_state & CAPS)
break;
shift_state |= CAPS;
lock_state ^= CAPS;
async_update();
break;
case SCROLL:
if (dt & 0x80) {
shift_state &= ~SCROLL;
break;
}
if (shift_state & SCROLL)
break;
shift_state |= SCROLL;
lock_state ^= SCROLL;
if ((lock_state & SCROLL) == 0)
wakeup((caddr_t)&lock_state);
async_update();
break;
}
return capchar;
}
#endif /* 0 */
switch (dt) {
case KBR_EXTENDED:
extended = 1;
goto loop;
}
#ifdef DDB
/*
* Check for cntl-alt-esc.
*/
if ((dt == 1) && (shift_state & (CTL | ALT)) == (CTL | ALT)) {
Debugger();
dt |= 0x80; /* discard esc (ddb discarded ctl-alt) */
}
#endif
/*
* Check for make/break.
*/
if (dt & 0x80) {
/*
* break
*/
dt &= 0x7f;
switch (scan_codes[dt].type) {
case NUM:
shift_state &= ~NUM;
break;
case CAPS:
shift_state &= ~CAPS;
break;
case SCROLL:
shift_state &= ~SCROLL;
break;
case SHIFT:
shift_state &= ~SHIFT;
break;
case ALT:
shift_state &= ~ALT;
break;
case CTL:
shift_state &= ~CTL;
break;
}
} else {
/*
* make
*/
switch (scan_codes[dt].type) {
/*
* locking keys
*/
case NUM:
if (shift_state & NUM)
break;
shift_state |= NUM;
lock_state ^= NUM;
async_update();
break;
case CAPS:
if (shift_state & CAPS)
break;
shift_state |= CAPS;
lock_state ^= CAPS;
async_update();
break;
case SCROLL:
if (shift_state & SCROLL)
break;
shift_state |= SCROLL;
lock_state ^= SCROLL;
if ((lock_state & SCROLL) == 0)
wakeup((caddr_t)&lock_state);
async_update();
break;
/*
* non-locking keys
*/
case SHIFT:
shift_state |= SHIFT;
break;
case ALT:
shift_state |= ALT;
break;
case CTL:
shift_state |= CTL;
break;
case ASCII:
/* control has highest priority */
if (shift_state & CTL)
capchar[0] = scan_codes[dt].ctl[0];
else if (shift_state & SHIFT)
capchar[0] = scan_codes[dt].shift[0];
else
capchar[0] = scan_codes[dt].unshift[0];
if ((lock_state & CAPS) && capchar[0] >= 'a' &&
capchar[0] <= 'z') {
capchar[0] -= ('a' - 'A');
}
capchar[0] |= (shift_state & ALT);
extended = 0;
return capchar;
case NONE:
break;
case FUNC: {
char *more_chars;
if (shift_state & SHIFT)
more_chars = scan_codes[dt].shift;
else if (shift_state & CTL)
more_chars = scan_codes[dt].ctl;
else
more_chars = scan_codes[dt].unshift;
extended = 0;
return more_chars;
}
case KP: {
char *more_chars;
if (shift_state & (SHIFT | CTL) ||
(lock_state & NUM) == 0 || extended)
more_chars = scan_codes[dt].shift;
else
more_chars = scan_codes[dt].unshift;
extended = 0;
return more_chars;
}
}
}
extended = 0;
loop:
if ((inb(KBSTATP) & KBS_DIB) == 0)
return 0;
goto top;
}
/* ARGSUSED */
int
pccngetc(cookie)
void *cookie;
{
register char *cp;
#if 0
if (pc_xmode > 0)
return 0;
#endif
do {
/* wait for byte */
while ((inb(KBSTATP) & KBS_DIB) == 0);
/* see if it's worthwhile */
cp = sget();
} while (!cp);
if (*cp == '\r')
return '\n';
return *cp;
}
void
pccnpollc(cookie, on)
void *cookie;
int on;
{
struct pckbd_softc *sc = cookie;
polling = on;
if (!on) {
int s;
/*
* If disabling polling on a device that's been configured,
* make sure there are no bytes left in the FIFO, holding up
* the interrupt line. Otherwise we won't get any further
* interrupts.
*/
if (sc != 0) {
s = spltty();
pckbdintr(sc);
splx(s);
}
}
}