From: Russell King <rmk@arm.linux.org.uk>
Add console_stop() and console_start() methods so the serial drivers
can disable console output before suspending a port, and re-enable output
afterwards.
We also add locking to ensure that we synchronise with any in-progress
printk.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/serial/serial_core.c | 4 ++--
25-akpm/include/linux/console.h | 2 ++
25-akpm/kernel/printk.c | 21 +++++++++++++++++++++
3 files changed, 25 insertions(+), 2 deletions(-)
diff -puN drivers/serial/serial_core.c~provide-console_suspend-and-console_resume drivers/serial/serial_core.c
--- 25/drivers/serial/serial_core.c~provide-console_suspend-and-console_resume 2004-06-28 00:58:58.516883064 -0700
+++ 25-akpm/drivers/serial/serial_core.c 2004-06-28 00:58:58.524881848 -0700
@@ -1923,7 +1923,7 @@ int uart_suspend_port(struct uart_driver
* Disable the console device before suspending.
*/
if (uart_console(port))
- port->cons->flags &= ~CON_ENABLED;
+ console_stop(port->cons);
uart_change_pm(state, 3);
@@ -1945,7 +1945,7 @@ int uart_resume_port(struct uart_driver
*/
if (uart_console(port)) {
uart_change_speed(state, NULL);
- port->cons->flags |= CON_ENABLED;
+ console_start(port->cons);
}
if (state->info && state->info->flags & UIF_INITIALIZED) {
diff -puN include/linux/console.h~provide-console_suspend-and-console_resume include/linux/console.h
--- 25/include/linux/console.h~provide-console_suspend-and-console_resume 2004-06-28 00:58:58.518882760 -0700
+++ 25-akpm/include/linux/console.h 2004-06-28 00:58:58.525881696 -0700
@@ -105,6 +105,8 @@ extern void release_console_sem(void);
extern void console_conditional_schedule(void);
extern void console_unblank(void);
extern struct tty_driver *console_device(int *);
+extern void console_stop(struct console *);
+extern void console_start(struct console *);
extern int is_console_locked(void);
/* Some debug stub to catch some of the obvious races in the VT code */
diff -puN kernel/printk.c~provide-console_suspend-and-console_resume kernel/printk.c
--- 25/kernel/printk.c~provide-console_suspend-and-console_resume 2004-06-28 00:58:58.519882608 -0700
+++ 25-akpm/kernel/printk.c 2004-06-28 00:58:58.526881544 -0700
@@ -704,6 +704,27 @@ struct tty_driver *console_device(int *i
}
/*
+ * Prevent further output on the passed console device so that (for example)
+ * serial drivers can disable console output before suspending a port, and can
+ * re-enable output afterwards.
+ */
+void console_stop(struct console *console)
+{
+ acquire_console_sem();
+ console->flags &= ~CON_ENABLED;
+ release_console_sem();
+}
+EXPORT_SYMBOL(console_stop);
+
+void console_start(struct console *console)
+{
+ acquire_console_sem();
+ console->flags |= CON_ENABLED;
+ release_console_sem();
+}
+EXPORT_SYMBOL(console_start);
+
+/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
* print any messages that were printed by the kernel before the
_