Correctly handle the case of a system setup to use glass console, which

frame buffer has been removed, but which keyboard is left plugged in.
The PROM will select a `keyboard input, serial output' console, which was
being recognized as glass console by the kernel. The kernel would then
reset the serial chip at zstty attach time, while still using the PROM
output routines at this point, and hang.

Fix this by paying attention to split input/output setups and always falling
back to serial console in this case.

ok kettenis@

1 files changed, 19 insertions, 1 deletions

diff --git a/sys/arch/sparc/dev/zs.c b/sys/arch/sparc/dev/zs.c
index 10b9452daa8..49468c319fa 100644
--- a/sys/arch/sparc/dev/zs.c
+++ b/sys/arch/sparc/dev/zs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: zs.c,v 1.48 2010/07/10 19:32:24 miod Exp $	*/
+/*	$OpenBSD: zs.c,v 1.49 2012/05/25 17:11:40 miod Exp $	*/
 /*	$NetBSD: zs.c,v 1.50 1997/10/18 00:00:40 gwr Exp $	*/
 
 /*-
@@ -1099,6 +1099,24 @@ setup_console:
 
 	if (inSource != outSink) {
 		printf("cninit: mismatched PROM output selector\n");
+		/*
+		 * In case of mismatch, force the console to be on
+		 * serial.
+		 * There are three possible mismatches:
+		 * - input and output on different serial lines:
+		 *   use the output line.
+		 * - input on keyboard, output on serial:
+		 *   use the output line (this allows systems configured
+		 *   for glass console, which frame buffers have been removed,
+		 *   to still work if the keyboard is left plugged).
+		 * - input on serial, output on video:
+		 *   use the input line, since we don't know if a keyboard
+		 *   is connected.
+		 */
+		if (outSink == PROMDEV_TTYA || outSink == PROMDEV_TTYB)
+			inSource = outSink;
+		else
+			outSink = inSource;
 	}
 
 	switch (inSource) {