Optimizations to the AT keyboard driver to reduce unnecessary delays during the FreeBSD boot process

share/man/man4/atkbdc.4

@@ -24,7 +24,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd February 26, 2023
+.Dd August 29, 2025
 .Dt ATKBDC 4
 .Os
 .Sh NAME
@@ -36,12 +36,17 @@
 .Cd "options KBD_DELAY1=N"
 .Cd "options KBD_DELAY2=N"
 .Cd "options KBDIO_DEBUG=N"
+.Cd "options RESET_DELAY_DIVISION_FACTOR=N"
 .Cd "device atkbdc"
 .Pp
 In
 .Pa /boot/device.hints :
 .Cd hint.atkbdc.0.at="isa"
 .Cd hint.atkbdc.0.port="0x060"
+.Pp
+In
+.Pa /boot/loader.conf :
+.Cd hw.atkbd.short_delay
 .Sh DESCRIPTION
 The keyboard controller
 .Nm
@@ -101,6 +106,21 @@ The default value is 100ms.
 Sets the debug level to
 .Fa N .
 The default value is zero, which suppresses all debugging output.
+.It Em RESET_DELAY_DIVISION_FACTOR=N
+The default value is 40. It is suppose to divide original 200ms delay by 40 and result 5ms delay for modern hardware.
+.El
+.Ss Tunables
+The following tunable can be set at the
+.Xr loader 8
+prompt or in
+.Pa /boot/loader.conf :
+.Bl -tag -width indent
+.It Va hw.atkbd.short_delay
+The default value is one, which enables shorter delays during controller
+initialization.  Setting this to zero restores the original, longer delays.
+Using shorter delays can significantly improve boot time on modern
+systems, but may cause problems on some legacy hardware that requires
+longer timing for reliable operation.
 .El
 .\".Ss Driver Flags
 .\".Sh FILES
@@ -124,3 +144,5 @@ The kbdio module, the
 .Nm
 driver and this manual page were written by
 .An Kazutaka Yokota Aq Mt [email protected] .
+Then updated by
+.An Lahiru Gunathilake Aq Mt [email protected] .

stand/libsa/zfs/zfsimpl.c

@@ -34,6 +34,8 @@
 #include <sys/stdint.h>
 #include <sys/list.h>
 #include <sys/zfs_bootenv.h>
+#include <sys/tslog.h>
+
 #include <machine/_inttypes.h>
 
 #include "zfsimpl.h"
@@ -162,11 +164,14 @@ vdev_indirect_mapping_entry_phys_t *
 static void
 zfs_init(void)
 {
+	TSENTER();
 	STAILQ_INIT(&zfs_pools);
 
 	dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
 
 	zfs_init_crc();
+	TSEXIT();
+
 #ifdef HAS_ZSTD_ZFS
 	zstd_init();
 #endif

sys/dev/acpica/acpi.c

@@ -55,6 +55,7 @@
 #include <sys/smp.h>
 #include <sys/timetc.h>
 #include <sys/uuid.h>
+#include <sys/tslog.h>
 
 #if defined(__i386__) || defined(__amd64__)
 #include <machine/clock.h>
@@ -493,6 +494,7 @@ acpi_attach(device_t dev)
     char		*env;
     enum power_stype	stype;
 
+    TSENTER();
     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 
     sc = device_get_softc(dev);
@@ -769,7 +771,10 @@ acpi_attach(device_t dev)
 
     error = 0;
 
+    TSEXIT();
+
  out:
+    TSEXIT();
     return_VALUE (error);
 }
 

sys/dev/atkbdc/atkbd.c

@@ -384,11 +384,14 @@ atkbd_init(int unit, keyboard_t **kbdp, void *arg, int flags)
 	char phys_loc[8];
 #endif
 
+	TSENTER();
 	/* XXX */
 	if (unit == ATKBD_DEFAULT) {
 		*kbdp = kbd = &default_kbd;
-		if (KBD_IS_INITIALIZED(kbd) && KBD_IS_CONFIGURED(kbd))
+		if (KBD_IS_INITIALIZED(kbd) && KBD_IS_CONFIGURED(kbd)) {
+			TSEXIT();
 			return 0;
+		}
 		state = &default_kbd_state;
 		keymap = &default_keymap;
 		accmap = &default_accentmap;
@@ -410,6 +413,7 @@ atkbd_init(int unit, keyboard_t **kbdp, void *arg, int flags)
 			goto bad;
 		}
 	} else if (KBD_IS_INITIALIZED(*kbdp) && KBD_IS_CONFIGURED(*kbdp)) {
+		TSEXIT();
 		return 0;
 	} else {
 		kbd = *kbdp;
@@ -505,6 +509,7 @@ atkbd_init(int unit, keyboard_t **kbdp, void *arg, int flags)
 		KBD_CONFIG_DONE(kbd);
 	}
 
+	TSEXIT();
 	return 0;
 bad:
 	if (needfree) {
@@ -521,6 +526,8 @@ atkbd_init(int unit, keyboard_t **kbdp, void *arg, int flags)
 			*kbdp = NULL;	/* insure ref doesn't leak to caller */
 		}
 	}
+
+	TSEXIT();
 	return error;
 }
 
@@ -948,6 +955,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 	int ival;
 #endif
 
+	TSENTER();
 	s = spltty();
 	switch (cmd) {
 	case KDGKBMODE:		/* get keyboard mode */
@@ -978,6 +986,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 			break;
 		default:
 			splx(s);
+			TSEXIT();
 			return EINVAL;
 		}
 		break;
@@ -996,6 +1005,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 		/* NOTE: lock key state in ks_state won't be changed */
 		if (*(int *)arg & ~LOCK_MASK) {
 			splx(s);
+			TSEXIT();
 			return EINVAL;
 		}
 		i = *(int *)arg;
@@ -1012,6 +1022,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 					  ledmap[i & LED_MASK]);
 			if (error) {
 				splx(s);
+				TSEXIT();
 				return error;
 			}
 		}
@@ -1037,18 +1048,23 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 	case KDSKBSTATE:	/* set lock key state */
 		if (*(int *)arg & ~LOCK_MASK) {
 			splx(s);
+			TSEXIT();
 			return EINVAL;
 		}
 		state->ks_state &= ~LOCK_MASK;
 		state->ks_state |= *(int *)arg;
 		splx(s);
+
+		TSEXIT();
 		/* set LEDs and quit */
 		return atkbd_ioctl(kbd, KDSETLED, arg);
 
 	case KDSETREPEAT:	/* set keyboard repeat rate (new interface) */
 		splx(s);
-		if (!KBD_HAS_DEVICE(kbd))
+		if (!KBD_HAS_DEVICE(kbd)) {
+			TSEXIT();
 			return 0;
+		}
 		i = typematic(((int *)arg)[0], ((int *)arg)[1]);
 		error = write_kbd(state->kbdc, KBDC_SET_TYPEMATIC, i);
 		if (error == 0) {
@@ -1060,6 +1076,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 				evdev_push_repeats(state->ks_evdev, kbd);
 #endif
 		}
+		TSEXIT();
 		return error;
 
 #if defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD5) || \
@@ -1071,8 +1088,10 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 #endif
 	case KDSETRAD:		/* set keyboard repeat rate (old interface) */
 		splx(s);
-		if (!KBD_HAS_DEVICE(kbd))
+		if (!KBD_HAS_DEVICE(kbd)) {
+			TSEXIT();
 			return 0;
+		}
 		error = write_kbd(state->kbdc, KBDC_SET_TYPEMATIC, *(int *)arg);
 		if (error == 0) {
 			kbd->kb_delay1 = typematic_delay(*(int *)arg);
@@ -1083,6 +1102,7 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 				evdev_push_repeats(state->ks_evdev, kbd);
 #endif
 		}
+		TSEXIT();
 		return error;
 
 	case PIO_KEYMAP:	/* set keyboard translation table */
@@ -1096,10 +1116,13 @@ atkbd_ioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
 		/* FALLTHROUGH */
 	default:
 		splx(s);
+		TSEXIT();
 		return genkbd_commonioctl(kbd, cmd, arg);
 	}
 
 	splx(s);
+	TSEXIT();
+
 	return 0;
 }
 
@@ -1363,8 +1386,10 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 	int id;
 	int c;
 
+	TSENTER();
 	if (!kbdc_lock(kbdc, TRUE)) {
 		/* driver error? */
+		TSEXIT();
 		return EIO;
 	}
 
@@ -1378,6 +1403,7 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 		/* CONTROLLER ERROR */
 		kbdc_lock(kbdc, FALSE);
 		printf("atkbd: unable to get the current command byte value.\n");
+		TSEXIT();
 		return EIO;
 	}
 	if (bootverbose)
@@ -1393,12 +1419,14 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 		/* CONTROLLER ERROR: there is very little we can do... */
 		printf("atkbd: unable to set the command byte.\n");
 		kbdc_lock(kbdc, FALSE);
+		TSEXIT();
 		return EIO;
 	}
 
 	if (HAS_QUIRK(kbdc, KBDC_QUIRK_RESET_AFTER_PROBE) &&
 	    atkbd_reset(kbdc, flags, c)) {
 		kbdc_lock(kbdc, FALSE);
+		TSEXIT();
 		return EIO;
 	}
 
@@ -1449,6 +1477,7 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 	if (!HAS_QUIRK(kbdc, KBDC_QUIRK_RESET_AFTER_PROBE) &&
 	    atkbd_reset(kbdc, flags, c)) {
 		kbdc_lock(kbdc, FALSE);
+		TSEXIT();
 		return EIO;
 	}
 
@@ -1472,6 +1501,7 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 			    ? 0xff : KBD_KBD_CONTROL_BITS, c);
 			kbdc_lock(kbdc, FALSE);
 			printf("atkbd: unable to set the XT keyboard mode.\n");
+			TSEXIT();
 			return EIO;
 		}
 	}
@@ -1502,10 +1532,12 @@ init_keyboard(KBDC kbdc, int *type, int flags)
 			KBD_OVERRIDE_KBD_LOCK), c);
 		kbdc_lock(kbdc, FALSE);
 		printf("atkbd: unable to enable the keyboard port and intr.\n");
+		TSEXIT();
 		return EIO;
 	}
 
 	kbdc_lock(kbdc, FALSE);
+	TSEXIT();
 	return 0;
 }
 

sys/dev/atkbdc/atkbd_atkbdc.c

@@ -116,24 +116,30 @@ atkbdattach(device_t dev)
 	int rid;
 	int error;
 
+	TSENTER();
 	sc = device_get_softc(dev);
 
 	rid = KBDC_RID_KBD;
 	irq = bus_get_resource_start(dev, SYS_RES_IRQ, rid);
 	flags = device_get_flags(dev);
 	error = atkbd_attach_unit(dev, &kbd, irq, flags);
-	if (error)
+	if (error) {
+		TSEXIT();
 		return error;
+	}
 
 	/* declare our interrupt handler */
 	sc->intr = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE);
-	if (sc->intr == NULL)
+	if (sc->intr == NULL) {
+		TSEXIT();
 		return ENXIO;
+	}
 	error = bus_setup_intr(dev, sc->intr, INTR_TYPE_TTY, NULL, atkbdintr,
 			       kbd, &sc->ih);
 	if (error)
 		bus_release_resource(dev, SYS_RES_IRQ, rid, sc->intr);
 
+	TSEXIT();
 	return error;
 }