pckbd: don't change translation mode if controller is in table 2

This was changed a decade ago to forcibly try table 3 first in order
to make some now-long-gone hardware work.

Newer Lenovo machines seem to have trouble being asked to change
modes which manifests as a long boot delay as it waits for each
request to timeout, or by causing the keyboard to generate junk when
typing.

Assume table 2 by default and just leave it alone if it's already
there.  This is how Linux has operated for quite a while and seems
to help on these Lenovo machines.

Tested by a few with these machines and has been in snaps for a bit.

diff --git a/sys/dev/pckbc/pckbd.c b/sys/dev/pckbc/pckbd.c
index 4b9bdfe..100f28c 100644 (file)
--- a/sys/dev/pckbc/pckbd.c
+++ b/sys/dev/pckbc/pckbd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pckbd.c,v 1.43 2016/04/14 07:06:03 mlarkin Exp $ */
+/* $OpenBSD: pckbd.c,v 1.44 2018/01/06 18:51:20 jcs Exp $ */
 /* $NetBSD: pckbd.c,v 1.24 2000/06/05 22:20:57 sommerfeld Exp $ */
 
 /*-
@@ -214,8 +214,7 @@ int
 pckbd_set_xtscancode(pckbc_tag_t kbctag, pckbc_slot_t kbcslot,
     struct pckbd_internal *id)
 {
-       /* default to have the 8042 translate the keyboard with table 3. */
-       int table = 3;
+       int table;
 
        if (pckbc_xt_translation(kbctag)) {
 #ifdef DEBUG
@@ -234,12 +233,21 @@ pckbd_set_xtscancode(pckbc_tag_t kbctag, pckbc_slot_t kbcslot,
                if (id != NULL)
                        id->t_translating = 0;
        } else {
-               if (id != NULL)
+               if (id != NULL) {
                        id->t_translating = 1;
+                       if (id->t_table == 0) {
+                               /*
+                                * Don't bother explicitly setting into set 2,
+                                * it's the default.
+                                */
+                               id->t_table = 2;
+                               return (0);
+                       }
+               }
        }
 
        /* keep falling back until we hit a table that looks usable. */
-       for (; table >= 1; table--) {
+       for (table = 3; table >= 1; table--) {
                u_char cmd[2];
 #ifdef DEBUG
                printf("pckbd: trying table %d\n", table);