[RFC][PATCH -mm] Make it possible to disable serial console suspend

[Rafael J. Wysocki]

Hack uart_suspend_port() and uart_resume_port() so that serial console ports
are not suspended if CONFIG_DISABLE_CONSOLE_SUSPEND is set.

This makes it possible to debug the suspend and resume routines of all device
drivers as well as the lowest-level swsusp code with the help of the serial
console.

Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
 drivers/serial/serial_core.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+)

Index: linux-2.6.18-rc4-mm3/drivers/serial/serial_core.c
===================================================================
--- linux-2.6.18-rc4-mm3.orig/drivers/serial/serial_core.c
+++ linux-2.6.18-rc4-mm3/drivers/serial/serial_core.c
@@ -1930,6 +1930,13 @@ int uart_suspend_port(struct uart_driver
 
 	mutex_lock(&state->mutex);
 
+#ifdef CONFIG_DISABLE_CONSOLE_SUSPEND
+	if (uart_console(port)) {
+		mutex_unlock(&state->mutex);
+		return 0;
+	}
+#endif
+
 	if (state->info && state->info->flags & UIF_INITIALIZED) {
 		const struct uart_ops *ops = port->ops;
 
@@ -1968,6 +1975,13 @@ int uart_resume_port(struct uart_driver 
 
 	mutex_lock(&state->mutex);
 
+#ifdef CONFIG_DISABLE_CONSOLE_SUSPEND
+	if (uart_console(port)) {
+		mutex_unlock(&state->mutex);
+		return 0;
+	}
+#endif
+
 	uart_change_pm(state, 0);
 
 	/*
-
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