ARM: clps711x: serial driver hungs are a result of call disable_irq within ISR

commit 7a6fbc9a887193a1e9f8658703881c528040afbc upstream.

Since 2.6.30-rc1 clps711x serial driver hungs system. This is a result
of call disable_irq from ISR. synchronize_irq waits for end of interrupt
and goes to infinite loop. This patch fix this problem.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c
index e6c3dbd781d..836fe273123 100644
--- a/drivers/tty/serial/clps711x.c
+++ b/drivers/tty/serial/clps711x.c
@@ -154,10 +154,9 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
                 port->x_char = 0;
                 return IRQ_HANDLED;
         }
-        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
-                clps711xuart_stop_tx(port);
-                return IRQ_HANDLED;
-        }
+
+        if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+                goto disable_tx_irq;
 
         count = port->fifosize >> 1;
         do {
@@ -171,8 +170,11 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                 uart_write_wakeup(port);
 
-        if (uart_circ_empty(xmit))
-                clps711xuart_stop_tx(port);
+        if (uart_circ_empty(xmit)) {
+        disable_tx_irq:
+                disable_irq_nosync(TX_IRQ(port));
+                tx_enabled(port) = 0;
+        }
 
         return IRQ_HANDLED;
 }