On Wed, Sep 19, 2012 at 06:52:32AM -0500, Jason Wessel wrote:
[...]

quoted

--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c

@@ -145,6 +145,8 @@ __setup("kgdboc=", kgdboc_option_setup);
 
 static void cleanup_kgdboc(void)
 {
+	if (kgdb_unregister_nmi_console())
+		return;
 	kgdboc_unregister_kbd();
 	if (configured == 1)
 		kgdb_unregister_io_module(&kgdboc_io_ops);

@@ -198,6 +200,10 @@ do_register:
 	if (err)
 		goto noconfig;
 
+	err = kgdb_register_nmi_console();
+	if (err)
+		goto noconfig;
+

Just one question on this one, what do you expect to happen, or how
does this work when you use a different serial port for example on a
board that has a real serial port and an FIQ port?   It was not
obvious that there was a path to check if the port you are
registering is an FIQ enabled port and then call the
kgdb_register_nmi_console at that point.

Yes, it works perfectly fine. If the port is not FIQ-enabled (which,
technically, can be enabled later -- it's just not implemented), then
ttyNMI just won't able to receive data.

The reason why I register nmi console in KGDB code (as opposite to arch
code), is the dependcy: the port should be initialized before it can be
used as ttyNMI. We could place the ttyNMI registration code into
late_initcall in arch/, and check for dbg_io_ops, but that is ugly by
itself, plus dbg_io_ops can change.

But with your kgdb_arch->enable_nmi suggestion (which I'll surely
implement), we can skip the registration at least for the cases when
the arch doesn't have this feature.

Thanks!

Anton.