From 6a597a38cbaf067019db96645f36e0b1f01f306a Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 10 Jan 2016 14:39:33 -0800 Subject: [PATCH] serial: 8250: Remove low_latency workaround The defunct low_latency input steering executed flush_to_ldisc() directly from interrupt context so dropping the port lock was necessary to avoid deadlock. That steering was removed by commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25 Author: Peter Hurley Date: Sat Feb 22 07:31:21 2014 -0500 tty: Fix low_latency BUG Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 48680565c991..9ef77a52c4f2 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1489,9 +1489,8 @@ unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr) break; lsr = serial_in(up, UART_LSR); } while (lsr & (UART_LSR_DR | UART_LSR_BI)); - spin_unlock(&port->lock); + tty_flip_buffer_push(&port->state->port); - spin_lock(&port->lock); return lsr; } EXPORT_SYMBOL_GPL(serial8250_rx_chars); -- 2.20.1