Switch the default terminal emulation style to xterm for most platforms.

Right now syscons(4) uses a cons25-style terminal emulator. The
disadvantages of that are:

- Little compatibility with embedded devices with serial interfaces.
- Bad bandwidth efficiency, mainly because of the lack of scrolling
  regions.
- A very hard transition path to support for modern character sets like
  UTF-8.

Our terminal emulation library, libteken, has been supporting
xterm-style terminal emulation for months, so flip the switch and make
everyone use an xterm-style console driver.

I still have to enable this on i386. Right now pc98 and i386 share the
same /etc/ttys file. I'm not going to switch pc98, because it uses its
own Kanji-capable cons25 emulator.

IMPORTANT: What to do if things go wrong (i.e. graphical artifacts):

- Run the application inside script(1), try to reduce the problem and
  send me the log file.
- In the mean time, you can run `vidcontrol -T cons25' and `export
  TERM=cons25' so you can run applications the same way you did before.
  You can also build your kernel with `options TEKEN_CONS25' to make all
  virtual terminals use the cons25 emulator by default.

Discussed on:	current@

1 files changed, 11 insertions, 2 deletions

diff --git a/sys/dev/syscons/scterm-teken.c b/sys/dev/syscons/scterm-teken.c
index 12b040e..fe8a186 100644
--- a/sys/dev/syscons/scterm-teken.c
+++ b/sys/dev/syscons/scterm-teken.c
@@ -50,6 +50,15 @@ __FBSDID("$FreeBSD$");
 
 #include <teken/teken.h>
 
+#if defined(TEKEN_XTERM) && defined(TEKEN_CONS25)
+#error "xterm and cons25 are mutually exclusive."
+#endif
+
+/* XXX: Use cons25 on i386, for compatibility with pc98. */
+#if defined(__i386__) && !defined(TEKEN_XTERM) && !defined(TEKEN_CONS25)
+#define	TEKEN_CONS25
+#endif
+
 static void scteken_revattr(unsigned char, teken_attr_t *);
 static unsigned int scteken_attr(const teken_attr_t *);
 
@@ -132,9 +141,9 @@ scteken_init(scr_stat *scp, void **softc, int code)
 #ifndef TEKEN_UTF8
 		teken_set_8bit(&ts->ts_teken);
 #endif /* !TEKEN_UTF8 */
-#ifndef TEKEN_XTERM
+#ifdef TEKEN_CONS25
 		teken_set_cons25(&ts->ts_teken);
-#endif /* !TEKEN_XTERM */
+#endif /* TEKEN_CONS25 */
 
 		tp.tp_row = scp->ysize;
 		tp.tp_col = scp->xsize;