[PATCH] Make serial console work for any port

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

The current serial console code only works for ports that are either
defined in SERIAL_PORT_DFNS (and set up by serial8250_isa_init_ports())
or registered by early_serial_setup().

On ia64, SERIAL_PORT_DFNS is empty because we discover everything
via ACPI and PCI.  And we only use early_serial_setup() for one port
described by the HCDP firmware table.

This patch against 2.6.3-rc2 makes it work for any valid port.  If we
don't know about the port early, we just return -ENODEV from the
setup() function, which leaves the serial console disabled.  After the
driver has found all the ports, we try to register the serial console
again if it hasn't been enabled already.

I think the "port->type = PORT_UNKNOWN" test is cleaner than the
"port->ops" test -- it more clearly gets to the point of "do we know
about this port".


=== drivers/serial/8250.c 1.43 vs edited ==--- 1.43/drivers/serial/8250.c	Fri Jan  2 12:35:07 2004
+++ edited/drivers/serial/8250.c	Wed Feb 11 13:13:11 2004
@@ -1976,6 +1976,8 @@
 	if (co->index >= UART_NR)
 		co->index = 0;
 	port = &serial8250_ports[co->index].port;
+	if (port->type = PORT_UNKNOWN)
+		return -ENODEV;
 
 	/*
 	 * Temporary fix.
@@ -2006,6 +2008,14 @@
 	return 0;
 }
 console_initcall(serial8250_console_init);
+
+static int __init serial8250_late_console_init(void)
+{
+	if (!(serial8250_console.flags & CON_ENABLED))
+		register_console(&serial8250_console);
+	return 0;
+}
+late_initcall(serial8250_late_console_init);
 
 #define SERIAL8250_CONSOLE	&serial8250_console
 #else
=== drivers/serial/serial_core.c 1.78 vs edited ==--- 1.78/drivers/serial/serial_core.c	Sat Jan 24 14:53:13 2004
+++ edited/drivers/serial/serial_core.c	Wed Feb 11 12:36:12 2004
@@ -1871,9 +1871,6 @@
 	if (flow = 'r')
 		termios.c_cflag |= CRTSCTS;
 
-	if (!port->ops)
-		return 0;	/* "console=" on ia64 */
-
 	port->ops->set_termios(port, &termios, NULL);
 	co->cflag = termios.c_cflag;