Commit f61051cd authored Jan 07, 2006 by Russell King Committed by Russell King Jan 07, 2006

[SERIAL] Fix clocal wakeup problem



Jim Alexander reported a problem where "if one calls open() in
blocking mode with CLOCAL off, the 8250.c driver under the 2.6
kernel (or at least 2.6.8 and 2.6.10) does not wake up the
blocked process when DCD is asserted."

Fix this by enabling modem status interrupts immediately before
we read the carrier detect status.

Thanks to Jim for reporting the problem and testing the fix.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent b9abaa3f

drivers/serial/serial_core.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1440,6 +1440,7 @@ uart_block_til_ready(struct file filp, struct uart_state state)
		* modem is ready for us.
		*/
		spin_lock_irq(&port->lock);
		port->ops->enable_ms(port);
		mctrl = port->ops->get_mctrl(port);
		spin_unlock_irq(&port->lock);
		if (mctrl & TIOCM_CAR)