[PATCH v4 15/21] serial: omap: unlock the port lock

From: Felipe Balbi
Date: Thu Sep 06 2012 - 08:51:00 EST


From: Ruchika Kharwar <ruchika@xxxxxx>

This patch unlocks the port lock before calling a serial_core API
and re-acquires the port lock after calling it.
This patch fixes a system freeze issue seen when the serial_core
API uart_write_wakeup() eventually attempts to acquire the port lock
already acquired by omap serial interrupt handler.

Tested-by: Shubhrajyoti D <shubhrajyoti@xxxxxx>
Signed-off-by: Ruchika Kharwar <ruchika@xxxxxx>
Signed-off-by: Pavan Savoy <pavan_savoy@xxxxxx>
Signed-off-by: Vijay Badawadagi <bvijay@xxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/tty/serial/omap-serial.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index d244163..9e4419c 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -224,8 +224,11 @@ static void transmit_chars(struct uart_omap_port *up, unsigned int lsr)
break;
} while (--count > 0);

- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) {
+ spin_unlock(&up->port.lock);
uart_write_wakeup(&up->port);
+ spin_lock(&up->port.lock);
+ }

if (uart_circ_empty(xmit))
serial_omap_stop_tx(&up->port);
--
1.7.12.rc3

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