diff -urN 2.4.5-clean/Documentation/Configure.help linux/Documentation/Configure.help
--- 2.4.5-clean/Documentation/Configure.help	Thu May 24 18:03:06 2001
+++ linux/Documentation/Configure.help	Fri Jun 15 13:34:18 2001
@@ -13274,6 +13274,21 @@
   If you are unsure, say N and read the HOWTO nevertheless: it will
   tell you what you have.
 
+PS/2 Keyboard Filter support
+CONFIG_PC_KEYB_FILTER
+  This enables filter support in the PS/2 keyboard driver.  With
+  this enabled, other drivers will be able to register with the
+  PS/2 driver and filter all incoming scancodes.  This is useful
+  for keyboards which extend the PS/2 keyboard standard with
+  non-standard scancodes which should not be normally routed to
+  the current console.
+
+  This option does not actually filter any scancodes, it only
+  allows other drivers (who will do the filtering) to register
+  with the PS/2 driver.
+
+  If unsure, say N.
+
 QIC-02 tape support
 CONFIG_QIC02_TAPE
   If you have a non-SCSI tape drive like that, say Y. Or, if you want
diff -urN 2.4.5-clean/drivers/char/Config.in linux/drivers/char/Config.in
--- 2.4.5-clean/drivers/char/Config.in	Tue Mar  6 22:44:34 2001
+++ linux/drivers/char/Config.in	Fri Jun 15 13:34:18 2001
@@ -105,6 +105,11 @@
 
 source drivers/char/joystick/Config.in
 
+mainmenu_option next_comment
+comment 'Keyboards'
+bool 'PS/2 Keyboard Filter support' CONFIG_PC_KEYB_FILTER
+endmenu
+
 tristate 'QIC-02 tape support' CONFIG_QIC02_TAPE
 if [ "$CONFIG_QIC02_TAPE" != "n" ]; then
    bool '  Do you want runtime configuration for QIC-02' CONFIG_QIC02_DYNCONF
diff -urN 2.4.5-clean/drivers/char/Makefile linux/drivers/char/Makefile
--- 2.4.5-clean/drivers/char/Makefile	Wed May 16 13:27:02 2001
+++ linux/drivers/char/Makefile	Fri Jun 15 13:34:18 2001
@@ -21,7 +21,7 @@
 # All of the (potential) objects that export symbols.
 # This list comes from 'grep -l EXPORT_SYMBOL *.[hc]'.
 
-export-objs     :=	busmouse.o console.o keyboard.o sysrq.o \
+export-objs     :=	busmouse.o console.o keyboard.o pc_keyb.o sysrq.o \
 			misc.o pty.o random.o selection.o serial.o \
 			tty_io.o
 
diff -urN 2.4.5-clean/drivers/char/pc_keyb.c linux/drivers/char/pc_keyb.c
--- 2.4.5-clean/drivers/char/pc_keyb.c	Fri Apr  6 13:42:55 2001
+++ linux/drivers/char/pc_keyb.c	Fri Jun 15 13:34:18 2001
@@ -13,6 +13,11 @@
  * Code fixes to handle mouse ACKs properly.
  * C. Scott Ananian <cananian@alumni.princeton.edu> 1999-01-29.
  *
+ * Added optional scancode filtering, used in keyboards which
+ * (incompatibly) extend the standard PS/2 specification.
+ * Also added synchronized output writing using a semaphore.
+ * Dan Streetman <ddstreet@us.ibm.com> 2001-03-14
+ *
  */
 
 #include <linux/config.h>
@@ -32,6 +37,7 @@
 #include <linux/slab.h>
 #include <linux/kbd_kern.h>
 #include <linux/smp_lock.h>
+#include <linux/module.h>
 
 #include <asm/keyboard.h>
 #include <asm/bitops.h>
@@ -60,6 +66,7 @@
 
 static void kbd_write_command_w(int data);
 static void kbd_write_output_w(int data);
+static void kb_wait(void);
 #ifdef CONFIG_PSMOUSE
 static void aux_write_ack(int val);
 static void __aux_write_ack(int val);
@@ -68,7 +75,7 @@
 static spinlock_t kbd_controller_lock = SPIN_LOCK_UNLOCKED;
 static unsigned char handle_kbd_event(void);
 
-/* used only by send_data - set by keyboard_interrupt */
+/* used by send_data and send_data_buffer - set by keyboard_interrupt */
 static volatile unsigned char reply_expected;
 static volatile unsigned char acknowledge;
 static volatile unsigned char resend;
@@ -94,6 +101,104 @@
 #define MAX_RETRIES	60		/* some aux operations take long time*/
 #endif /* CONFIG_PSMOUSE */
 
+#ifdef CONFIG_PC_KEYB_FILTER
+/* Use an array (instead of a linked list) to save time in_interrupt() */
+static struct pc_keyb_filter *filters[PC_KEYB_MAX_FILTERS];
+static int num_filters = 0;
+
+static DECLARE_MUTEX(kbd_output_sema);
+static spinlock_t pc_keyb_filter_lock = SPIN_LOCK_UNLOCKED;
+
+static int send_data_buffer( unsigned char *buffer, unsigned int len, unsigned int *xferred, unsigned int retries, unsigned int timeout )
+{
+	const unsigned int timeout_jiffies = ( (timeout * HZ) + 999 ) / 1000;
+	int i;
+	unsigned int xfer = 0;
+
+	if (xferred) *xferred = 0;
+
+	if (down_interruptible(&kbd_output_sema))
+		return -EINTR;
+	for (i=0; i<len; i++) {
+		do {
+			timeout = timeout_jiffies;
+			acknowledge = resend = 0;
+			reply_expected = 1;
+			kbd_write_output_w( (int)buffer[i] );
+			while (timeout-- && !resend && !acknowledge) {
+				set_current_state(TASK_INTERRUPTIBLE);
+				if (schedule_timeout(1) && signal_pending(current)) {
+					set_current_state(TASK_RUNNING);
+					up(&kbd_output_sema);
+					return -EINTR;
+				}
+				set_current_state(TASK_RUNNING);
+			}
+#ifdef KBD_REPORT_TIMEOUTS
+			if (0 >= timeout)
+				printk( __FILE__ ": Timeout - AT keyboard not present?\n" );
+#endif
+		} while (retries-- && !acknowledge && resend);
+		if (acknowledge) {
+			xfer++;
+			if (xferred) *xferred = xfer;
+		} else {
+#ifdef KBD_REPORT_TIMEOUTS
+			if (resend)
+				printk( __FILE__ ": Too many NACKs - Noisy keyboard cable?\n" );
+#endif
+			break;
+		}
+	}
+	up(&kbd_output_sema);
+
+	return len == xfer ? 0 : -ETIMEDOUT;
+}
+#endif /* CONFIG_PC_KEYB_FILTER */
+
+int register_pc_keyb_filter( struct pc_keyb_filter *filter )
+{
+#ifdef CONFIG_PC_KEYB_FILTER
+	unsigned long flags;
+	int retval = 0;
+
+	spin_lock_irqsave(&pc_keyb_filter_lock, flags);
+	if (PC_KEYB_MAX_FILTERS > num_filters) {
+		filters[num_filters++] = filter;
+		filter->write_data = send_data_buffer;
+	} else {
+		retval = -EDQUOT;
+	}
+	spin_unlock_irqrestore(&pc_keyb_filter_lock, flags);
+	return retval;
+#else
+	return -ENOSYS;
+#endif
+}
+
+void unregister_pc_keyb_filter( struct pc_keyb_filter *filter )
+{
+#ifdef CONFIG_PC_KEYB_FILTER
+	unsigned long flags;
+	int i, found = 0;
+
+	spin_lock_irqsave(&pc_keyb_filter_lock, flags);
+	filter->write_data = NULL;
+	for (i=0; i<num_filters; i++) {
+		if (filters[i] == filter)
+			found = 1;
+		if (found && i+1<PC_KEYB_MAX_FILTERS)
+			filters[i] = filters[i+1];
+	}
+	if (found)
+		filters[num_filters--] = NULL;
+	spin_unlock_irqrestore(&pc_keyb_filter_lock, flags);
+#endif
+}
+
+EXPORT_SYMBOL(register_pc_keyb_filter);
+EXPORT_SYMBOL(unregister_pc_keyb_filter);
+
 /*
  * Wait for keyboard controller input buffer to drain.
  *
@@ -428,6 +533,18 @@
 
 static inline void handle_keyboard_event(unsigned char scancode)
 {
+#ifdef CONFIG_PC_KEYB_FILTER
+	int i;
+
+	spin_lock(&pc_keyb_filter_lock);
+	for (i=0; i<num_filters; i++) {
+		if (filters[i]->filter_scancode( &scancode )) {
+			spin_unlock(&pc_keyb_filter_lock);
+			return;
+		}
+	}
+	spin_unlock(&pc_keyb_filter_lock);
+#endif /* CONFIG_PC_KEYB_FILTER */
 #ifdef CONFIG_VT
 	kbd_exists = 1;
 	if (do_acknowledge(scancode))
@@ -527,10 +644,17 @@
 
 void pckbd_leds(unsigned char leds)
 {
+#ifdef CONFIG_PC_KEYB_FILTER
+	if (down_interruptible(&kbd_output_sema))
+		return;
+#endif
 	if (kbd_exists && (!send_data(KBD_CMD_SET_LEDS) || !send_data(leds))) {
 		send_data(KBD_CMD_ENABLE);	/* re-enable kbd if any errors */
 		kbd_exists = 0;
 	}
+#ifdef CONFIG_PC_KEYB_FILTER
+	up(&kbd_output_sema);
+#endif
 }
 
 /*
diff -urN 2.4.5-clean/include/linux/pc_keyb.h linux/include/linux/pc_keyb.h
--- 2.4.5-clean/include/linux/pc_keyb.h	Mon Oct 11 13:15:40 1999
+++ linux/include/linux/pc_keyb.h	Fri Jun 15 13:34:18 2001
@@ -6,6 +6,11 @@
  *	(c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
  */
 
+#ifndef __PC_KEYB_H
+#define __PC_KEYB_H
+
+#ifdef __KERNEL__
+
 /*
  *	Configuration Switches
  */
@@ -128,3 +133,17 @@
 	struct fasync_struct *fasync;
 	unsigned char buf[AUX_BUF_SIZE];
 };
+
+#define PC_KEYB_MAX_FILTERS		1
+
+struct pc_keyb_filter {
+	int (*filter_scancode)( unsigned char *scancode );
+	int (*write_data)( unsigned char *data, unsigned int length, unsigned int *xferred, unsigned int retries, unsigned int timeout );
+};
+
+int register_pc_keyb_filter( struct pc_keyb_filter *filter );
+void unregister_pc_keyb_filter( struct pc_keyb_filter *filter );
+
+#endif /* __KERNEL__ */
+
+#endif /* __PC_KEYB_H */