diff --git a/share/man/man4/pms.4 b/share/man/man4/pms.4
index 46e614fd0382..24924e47e5c4 100644
--- a/share/man/man4/pms.4
+++ b/share/man/man4/pms.4
@@ -1,4 +1,4 @@
-.\" $NetBSD: pms.4,v 1.32 2018/11/06 09:14:08 blymn Exp $
+.\" $NetBSD: pms.4,v 1.32.2.1 2020/03/30 18:45:16 martin Exp $
 .\"
 .\" Copyright (c) 1993 Christopher G. Demetriou
 .\" All rights reserved.
@@ -32,7 +32,7 @@
 .\"
 .\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
 .\"
-.Dd February 4, 2018
+.Dd March 30, 2020
 .Dt PMS 4
 .Os
 .Sh NAME
@@ -102,13 +102,22 @@ The following
 variables control behavior of Synaptics touchpads:
 .Bl -tag -width 8n
 .It Dv hw.synaptics.up_down_emulation
-If the touchpad reports the existence of Up/Down buttons, this value
-determines if they should be reported as button 4 and 5 events or if
-they should be used to emulate some other event.
-When set to 0, report Up/Down events as buttons 4 and 5.
-When set to 1, the Up and Down buttons are both mapped to the middle button.
-When set to 2 (default), the Up and Down buttons are used for Z-axis
-emulation, which more closely resembles how mouse wheels operate.
+If the touchpad reports the existence of extra ("Up/Down") buttons, this
+value determines what kind of mouse events they should generate.
+On certain clickpads, the Up/Down buttons may be physical buttons that
+can be used instead of pressing the pad down, or used as additional
+buttons.
+.Bl -bullet
+.It
+If set to 0, Up/Down events generate button 4 and 5 clicks.
+.It
+If set to 1, Up/Down events generate middle button clicks.
+.It
+If set to 2, the Up and Down buttons are used for Z-axis emulation,
+which more closely resembles how mouse wheels operate.
+.It
+If set to 3 (default), Up/Down events generate left/right clicks.
+.El
 .It Dv hw.synaptics.up_down_motion_delta
 When the Up/Down buttons are used for Z-axis emulation, this value specifies
 the emulated delta-Z value per click.
@@ -139,9 +148,14 @@ reported pressure drops below this value.
 More recent touchpads can report the presence of more than one finger
 on the pad.
 This value determines how such events are used.
+.Bl -bullet
+.It
 If set to 0 (default), two-finger events are ignored.
+.It
 If set to 1, two-finger events generate a right button click.
+.It
 If set to 2, two-finger events generate a middle button click.
+.El
 .It Dv hw.synaptics.scale_x
 .It Dv hw.synaptics.scale_y
 .It Dv hw.synaptics.scale_z
diff --git a/sys/dev/pckbport/synaptics.c b/sys/dev/pckbport/synaptics.c
index decb8dcd0ae9..58ffc2f84bed 100644
--- a/sys/dev/pckbport/synaptics.c
+++ b/sys/dev/pckbport/synaptics.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: synaptics.c,v 1.50 2019/07/05 05:09:24 mlelstv Exp $	*/
+/*	$NetBSD: synaptics.c,v 1.50.2.1 2020/03/30 18:45:16 martin Exp $	*/
 
 /*
  * Copyright (c) 2005, Steve C. Woodford
@@ -48,7 +48,7 @@
 #include "opt_pms.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: synaptics.c,v 1.50 2019/07/05 05:09:24 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: synaptics.c,v 1.50.2.1 2020/03/30 18:45:16 martin Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -98,7 +98,7 @@ static void pms_sysctl_synaptics(struct sysctllog **);
 static int pms_sysctl_synaptics_verify(SYSCTLFN_ARGS);
 
 /* Controlled by sysctl. */
-static int synaptics_up_down_emul = 2;
+static int synaptics_up_down_emul = 3;
 static int synaptics_up_down_motion_delta = 1;
 static int synaptics_gesture_move = 200;
 static int synaptics_gesture_length = 20;
@@ -852,8 +852,11 @@ pms_sysctl_synaptics_verify(SYSCTLFN_ARGS)
 		return error;
 
 	/* Sanity check the params. */
-	if (node.sysctl_num == synaptics_up_down_emul_nodenum ||
-	    node.sysctl_num == synaptics_two_fingers_emul_nodenum) {
+	if (node.sysctl_num == synaptics_up_down_emul_nodenum) {
+		if (t < 0 || t > 3)
+			return (EINVAL);
+	} else
+	if (node.sysctl_num == synaptics_two_fingers_emul_nodenum) {
 		if (t < 0 || t > 2)
 			return (EINVAL);
 	} else
@@ -1091,13 +1094,29 @@ pms_synaptics_parse(struct pms_softc *psc)
 			/* Old style Middle Button. */
 			sp.sp_middle = (psc->packet[0] & PMS_LBUTMASK) ^
 		    	    (psc->packet[3] & PMS_LBUTMASK);
-		} else if (synaptics_up_down_emul == 1) {
+		} else if (synaptics_up_down_emul != 1) {
+			sp.sp_middle = 0;
+		}
+
+		switch (synaptics_up_down_emul) {
+		case 1:
 			/* Do middle button emulation using up/down buttons */
 			sp.sp_middle = sp.sp_up | sp.sp_down;
 			sp.sp_up = sp.sp_down = 0;
-		} else
-			sp.sp_middle = 0;
-
+			break;
+		case 3:
+			/* Do left/right button emulation using up/down buttons */
+			sp.sp_left = sp.sp_up;
+			sp.sp_right = sp.sp_down;
+			sp.sp_up = sp.sp_down = 0;
+			break;
+		default:
+			/*
+			 * Don't do any remapping...
+			 * Z-axis emulation is handled in pms_synaptics_process_packet
+			 */
+			break;
+		}
 	}
 
 	pms_synaptics_process_packet(psc, &sp);