ARM: clps711x: serial driver hungs are a result of call disable_irq within ISR
Alexander Shiyan [Tue, 27 Mar 2012 08:22:49 +0000 (12:22 +0400)]
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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/clps711x.c

index e6c3dbd..836fe27 100644 (file)
@@ -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;
 }