[SERIAL] Fix Bug 4900: S3 resume oops with irattach - Thinkpad A21m

If we fail to re-startup a serial port on resume, shut it down
immediately and mark it as an error condition.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 427a238..2331296 100644 (file)
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -209,33 +209,45 @@ static void uart_shutdown(struct uart_state *state)
        struct uart_info *info = state->info;
        struct uart_port *port = state->port;
 
-       if (!(info->flags & UIF_INITIALIZED))
-               return;
-
        /*
-        * Turn off DTR and RTS early.
+        * Set the TTY IO error marker
         */
-       if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
-               uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
+       if (info->tty)
+               set_bit(TTY_IO_ERROR, &info->tty->flags);
 
-       /*
-        * clear delta_msr_wait queue to avoid mem leaks: we may free
-        * the irq here so the queue might never be woken up.  Note
-        * that we won't end up waiting on delta_msr_wait again since
-        * any outstanding file descriptors should be pointing at
-        * hung_up_tty_fops now.
-        */
-       wake_up_interruptible(&info->delta_msr_wait);
+       if (info->flags & UIF_INITIALIZED) {
+               info->flags &= ~UIF_INITIALIZED;
 
-       /*
-        * Free the IRQ and disable the port.
-        */
-       port->ops->shutdown(port);
+               /*
+                * Turn off DTR and RTS early.
+                */
+               if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
+                       uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
+
+               /*
+                * clear delta_msr_wait queue to avoid mem leaks: we may free
+                * the irq here so the queue might never be woken up.  Note
+                * that we won't end up waiting on delta_msr_wait again since
+                * any outstanding file descriptors should be pointing at
+                * hung_up_tty_fops now.
+                */
+               wake_up_interruptible(&info->delta_msr_wait);
+
+               /*
+                * Free the IRQ and disable the port.
+                */
+               port->ops->shutdown(port);
+
+               /*
+                * Ensure that the IRQ handler isn't running on another CPU.
+                */
+               synchronize_irq(port->irq);
+       }
 
        /*
-        * Ensure that the IRQ handler isn't running on another CPU.
+        * kill off our tasklet
         */
-       synchronize_irq(port->irq);
+       tasklet_kill(&info->tlet);
 
        /*
         * Free the transmit buffer page.
@@ -244,15 +256,6 @@ static void uart_shutdown(struct uart_state *state)
                free_page((unsigned long)info->xmit.buf);
                info->xmit.buf = NULL;
        }
-
-       /*
-        * kill off our tasklet
-        */
-       tasklet_kill(&info->tlet);
-       if (info->tty)
-               set_bit(TTY_IO_ERROR, &info->tty->flags);
-
-       info->flags &= ~UIF_INITIALIZED;
 }
 
 /**
@@ -1928,14 +1931,25 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
 
        if (state->info && state->info->flags & UIF_INITIALIZED) {
                struct uart_ops *ops = port->ops;
+               int ret;
 
                ops->set_mctrl(port, 0);
-               ops->startup(port);
-               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);
+               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);
+               } 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.
+                        */
+                       state->info->flags &= ~UIF_INITIALIZED;
+                       uart_shutdown(state);
+               }
        }
 
        up(&state->sem);