[src/trunk]: src/sys/dev/pckbport Resynchronizing the input stream could infi...

[mlelstv <mlelstv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b66eb56c4868
branches:  trunk
changeset: 457585:b66eb56c4868
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Fri Jul 05 05:09:24 2019 +0000

description:
Resynchronizing the input stream could infinitely wait when the touchpad
is in the wrong (relative) mode. The detection of relative mode is never
reached.

Limit the resynchronization to 6 bytes, then trigger a reset.

diffstat:

 sys/dev/pckbport/synaptics.c |  15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diffs (51 lines):

diff -r 14c83531019a -r b66eb56c4868 sys/dev/pckbport/synaptics.c
--- a/sys/dev/pckbport/synaptics.c      Thu Jul 04 15:54:09 2019 +0000
+++ b/sys/dev/pckbport/synaptics.c      Fri Jul 05 05:09:24 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: synaptics.c,v 1.49 2019/06/02 08:55:00 blymn Exp $     */
+/*     $NetBSD: synaptics.c,v 1.50 2019/07/05 05:09:24 mlelstv 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 1.49 2019/06/02 08:55:00 blymn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: synaptics.c,v 1.50 2019/07/05 05:09:24 mlelstv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1154,7 +1154,7 @@
 
        getmicrouptime(&psc->current);
 
-       if (psc->inputstate > 0) {
+       if (psc->inputstate != 0) {
                timersub(&psc->current, &psc->last, &diff);
                if (diff.tv_sec > 0 || diff.tv_usec >= 40000) {
                        aprint_debug_dev(psc->sc_dev,
@@ -1173,14 +1173,23 @@
        psc->last = psc->current;
 
        switch (psc->inputstate) {
+       case -5:
+       case -4:
+       case -3:
+       case -2:
+       case -1:
        case 0:
                if ((data & 0xc8) != 0x80) {
                        aprint_debug_dev(psc->sc_dev,
                            "pms_input: 0x%02x out of sync\n", data);
+                       /* use negative counts to limit resync phase */
+                       psc->inputstate--;
                        return; /* not in sync yet, discard input */
                }
+               psc->inputstate = 0;
                /*FALLTHROUGH*/
 
+       case -6:
        case 3:
                if ((data & 8) == 8) {
                        aprint_debug_dev(psc->sc_dev,