This is a note to let you know that I've just added the patch titled

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

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also will be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 7a6fbc9a887193a1e9f8658703881c528040afbc Mon Sep 17 00:00:00 2001
From: Alexander Shiyan <[email protected]>
Date: Tue, 27 Mar 2012 12:22:49 +0400
Subject: ARM: clps711x: serial driver hungs are a result of call disable_irq
 within ISR

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 <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/tty/serial/clps711x.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c
index e6c3dbd..836fe273 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;
 }
-- 
1.7.10


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