special key (combo) for switching to K_XLATE

[Andriy Gapon]

Guys,

please take a look at the following hackish ugly code.
This is just a proof of concept.
It allows me to use an extended multimedia key (that generates 0xe0 0x32 code
sequence) on my keyboard to break out of K_RAW into K_XLATE.
The code is slightly tested and seems to work.
It allowed me to switch out of X terminal to a normal console terminal when X
server hanged. Then I could kill X and relatively easily recover from the
situation that previously require either a remote access (e.g. through network)
or a reboot.

What do you think about having such a capability in syscons?
Of course, the mode switch should be triggered by some key combination is
possible to produce on any/most supported keyboards and also should be hard to
press by accident.

Note that I haven't (again) checked this code with WITNESS.
diff --git a/sys/dev/syscons/syscons.c b/sys/dev/syscons/syscons.c
index d158f85..e543765 100644
--- a/sys/dev/syscons/syscons.c
+++ b/sys/dev/syscons/syscons.c
@@ -3127,6 +3127,7 @@ scgetc(sc_softc_t *sc, u_int flags)
 #endif
     u_int c;
     int this_scr;
+    static int e0 = 0;
     int f;
     int i;

@@ -3159,8 +3160,22 @@ next_code:
     if (!(flags & SCGETC_CN))
 	random_harvest(&c, sizeof(c), 1, 0, RANDOM_KEYBOARD);

-    if (scp->kbd_mode != K_XLATE)
+    if (scp->kbd_mode != K_XLATE) {
+	if (scp->kbd_mode == K_RAW) {
+	    if (e0) {
+		e0 = 0;
+		if (KEYCHAR(c) == 0x32) {
+		    printf("kbd_mode: %d => %d\n", scp->kbd_mode, K_XLATE);
+		    scp->kbd_mode = K_XLATE;
+		    kbdd_ioctl(scp->sc->kbd, KDSKBMODE, (caddr_t)&scp->kbd_mode);
+		    return NOKEY;
+		}
+	    }
+	    else if (KEYCHAR(c) == 0xe0)
+		e0 = 1;
+	}
 	return KEYCHAR(c);
+    }

     /* if scroll-lock pressed allow history browsing */
     if (!ISGRAPHSC(scp) && scp->history && scp->status & SLKED) {

-- 
Andriy Gapon