From c2684ed7d0e908e7c8dad7f199922d342ea55c66 Mon Sep 17 00:00:00 2001 From: Wan Ahmad Zainie Date: Wed, 6 Apr 2016 12:06:52 +0800 Subject: [PATCH] serial: 8250_pci: report DCD and DSR signals as active for Bay Trail Bay Trail UART port does not support DCD and DSR lines. The driver shall report that these signals are permanently active. This patch is for HSUART enumerated via PCI. For ACPI, see commit dfd37668ea6d ("serial: 8250_dw: Fix get_mctrl behaviour"). The commit also describes the possible issue if these signals are enabled on a port without these pins. Signed-off-by: Wan Ahmad Zainie Acked-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 4eedd1da32e6..0cf512377189 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1416,6 +1416,17 @@ static bool byt_dma_filter(struct dma_chan *chan, void *param) return true; } +static unsigned int +byt_get_mctrl(struct uart_port *port) +{ + unsigned int ret = serial8250_do_get_mctrl(port); + + /* Force DCD and DSR signals to permanently be reported as active. */ + ret |= TIOCM_CAR | TIOCM_DSR; + + return ret; +} + static int byt_serial_setup(struct serial_private *priv, const struct pciserial_board *board, @@ -1480,6 +1491,7 @@ byt_serial_setup(struct serial_private *priv, port->port.type = PORT_16550A; port->port.flags = (port->port.flags | UPF_FIXED_PORT | UPF_FIXED_TYPE); port->port.set_termios = byt_set_termios; + port->port.get_mctrl = byt_get_mctrl; port->port.fifosize = 64; port->tx_loadsz = 64; port->dma = dma; -- 2.39.5