target/linux/cns3xxx/patches-2.6.31/210-cns3xxx_smp_serial_fix.patch

   1 --- a/drivers/serial/8250.c
   2 +++ b/drivers/serial/8250.c
   3 @@ -1743,6 +1743,7 @@ static void serial8250_backup_timeout(un
   4         unsigned int iir, ier = 0, lsr;
   5         unsigned long flags;
   6
   7 +       spin_lock_irqsave(&up->port.lock, flags);
   8         /*
   9          * Must disable interrupts or else we risk racing with the interrupt
  10          * based handler.
  11 @@ -1760,10 +1761,8 @@ static void serial8250_backup_timeout(un
  12          * the "Diva" UART used on the management processor on many HP
  13          * ia64 and parisc boxes.
  14          */
  15 -       spin_lock_irqsave(&up->port.lock, flags);
  16         lsr = serial_in(up, UART_LSR);
  17         up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
  18 -       spin_unlock_irqrestore(&up->port.lock, flags);
  19         if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
  20             (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) &&
  21             (lsr & UART_LSR_THRE)) {
  22 @@ -1771,12 +1770,14 @@ static void serial8250_backup_timeout(un
  23                 iir |= UART_IIR_THRI;
  24         }
  25
  26 -       if (!(iir & UART_IIR_NO_INT))
  27 -               serial8250_handle_port(up);
  28 -
  29         if (is_real_interrupt(up->port.irq))
  30                 serial_out(up, UART_IER, ier);
  31
  32 +       spin_unlock_irqrestore(&up->port.lock, flags);
  33 +
  34 +       if (!(iir & UART_IIR_NO_INT))
  35 +               serial8250_handle_port(up);
  36 +
  37         /* Standard timer interval plus 0.2s to keep the port running */
  38         mod_timer(&up->timer,
  39                 jiffies + poll_timeout(up->port.timeout) + HZ / 5);