patch "serial: mvebu-uart: free the IRQ in ->shutdown()" added to tty-testing

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

    serial: mvebu-uart: free the IRQ in ->shutdown()

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-testing 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 be merged to the tty-next branch sometime soon, after it passes testing, and the merge window is open.

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

From: Thomas Petazzoni <[email protected]>
Date: Thu, 16 Jun 2016 16:48:52 +0200
Subject: serial: mvebu-uart: free the IRQ in ->shutdown()

As suggested by the serial port infrastructure documentation, the IRQ is requested in ->startup(). However, it is never freed in the ->shutdown() hook.

With simple systems that open the serial port once for all and always have at least one process that keep the serial port opened, there was no problem. But with a more complicated system (*cough* systemd *cough*), the serial port is opened/closed many times, which at some point no processes having the serial port open at all. Due to this ->startup() gets called again, tries to request_irq() again, which fails.

---
 drivers/tty/serial/mvebu-uart.c | 2 ++
 1 file changed, 2 insertions(+)

index ce362bd51de7..45b57c294d13 100644
@@ -300,6 +300,8 @@ static int mvebu_uart_startup(struct uart_port *port)
 static void mvebu_uart_shutdown(struct uart_port *port)
 {
 	writel(0, port->membase + UART_CTRL);
+
+	free_irq(port->irq, port);
 }
 
 static void mvebu_uart_set_termios(struct uart_port *port,

2.9.0