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Message-Id: <1253021938.6597.16.camel@hammer.suse.cz>
Date: Tue, 15 Sep 2009 15:38:58 +0200
From: Stanislav Brabec <utx@...guin.cz>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...e.de>,
Russell King - ARM Linux <linux@....linux.org.uk>
Subject: [PATCH] serial-core: resume serial hardware with no_console_suspend
Hardware may need re-initialization to get serial port working after
resume. It does not happen with no_console_suspend. Attached patch
attempts to fix it.
The patch attempts to keep hardware running before suspend and run
hardware re-initialization after resume. Maybe simpler approach is
possible.
Signed-off-by: Stanislav Brabec <sbrabec@...e.cz>
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index b0bb29d..43cc1ab 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1990,12 +1990,6 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
mutex_lock(&state->mutex);
- if (!console_suspend_enabled && uart_console(port)) {
- /* we're going to avoid suspending serial console */
- mutex_unlock(&state->mutex);
- return 0;
- }
-
tty_dev = device_find_child(port->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) {
enable_irq_wake(port->irq);
@@ -2003,20 +1997,23 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
mutex_unlock(&state->mutex);
return 0;
}
- port->suspended = 1;
+ if (console_suspend_enabled || !uart_console(port))
+ port->suspended = 1;
if (state->info.flags & UIF_INITIALIZED) {
const struct uart_ops *ops = port->ops;
int tries;
- state->info.flags = (state->info.flags & ~UIF_INITIALIZED)
- | UIF_SUSPENDED;
+ if (console_suspend_enabled || !uart_console(port)) {
+ state->info.flags = (state->info.flags & ~UIF_INITIALIZED)
+ | UIF_SUSPENDED;
- spin_lock_irq(&port->lock);
- ops->stop_tx(port);
- ops->set_mctrl(port, 0);
- ops->stop_rx(port);
- spin_unlock_irq(&port->lock);
+ spin_lock_irq(&port->lock);
+ ops->stop_tx(port);
+ ops->set_mctrl(port, 0);
+ ops->stop_rx(port);
+ spin_unlock_irq(&port->lock);
+ }
/*
* Wait for the transmitter to empty.
@@ -2031,16 +2028,18 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
drv->dev_name,
drv->tty_driver->name_base + port->line);
- ops->shutdown(port);
+ if (console_suspend_enabled || !uart_console(port))
+ ops->shutdown(port);
}
/*
* Disable the console device before suspending.
*/
- if (uart_console(port))
+ if (console_suspend_enabled && uart_console(port))
console_stop(port->cons);
- uart_change_pm(state, 3);
+ if (console_suspend_enabled || !uart_console(port))
+ uart_change_pm(state, 3);
mutex_unlock(&state->mutex);
@@ -2055,12 +2054,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
mutex_lock(&state->mutex);
- if (!console_suspend_enabled && uart_console(port)) {
- /* no need to resume serial console, it wasn't suspended */
- mutex_unlock(&state->mutex);
- return 0;
- }
-
tty_dev = device_find_child(port->dev, &match, serial_match_port);
if (!port->suspended && device_may_wakeup(tty_dev)) {
disable_irq_wake(port->irq);
@@ -2100,21 +2093,23 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
spin_lock_irq(&port->lock);
ops->set_mctrl(port, 0);
spin_unlock_irq(&port->lock);
- ret = ops->startup(port);
- if (ret == 0) {
- uart_change_speed(state, NULL);
- spin_lock_irq(&port->lock);
- ops->set_mctrl(port, port->mctrl);
- ops->start_tx(port);
- spin_unlock_irq(&port->lock);
- state->info.flags |= UIF_INITIALIZED;
- } else {
- /*
- * Failed to resume - maybe hardware went away?
- * Clear the "initialized" flag so we won't try
- * to call the low level drivers shutdown method.
- */
- uart_shutdown(state);
+ if (console_suspend_enabled || !uart_console(port)) {
+ ret = ops->startup(port);
+ if (ret == 0) {
+ uart_change_speed(state, NULL);
+ spin_lock_irq(&port->lock);
+ ops->set_mctrl(port, port->mctrl);
+ ops->start_tx(port);
+ spin_unlock_irq(&port->lock);
+ state->info.flags |= UIF_INITIALIZED;
+ } else {
+ /*
+ * Failed to resume - maybe hardware went away?
+ * Clear the "initialized" flag so we won't try
+ * to call the low level drivers shutdown method.
+ */
+ uart_shutdown(state);
+ }
}
state->info.flags &= ~UIF_SUSPENDED;
--
Best Regards / S pozdravem,
Stanislav Brabec
software developer
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