serial: 8250: Also set sticky MCR bits in console restoration

commit 6e6eebdf5e2455f089ccd000754a0deaeb79af82 upstream.

Sticky MCR bits are lost in console restoration if console suspending
has been disabled.  This currently affects the AFE bit, which works in
combination with RTS which we set, so we want to make sure the UART
retains control of its FIFO where previously requested.  Also specific
drivers may need other bits in the future.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Cc: stable@vger.kernel.org # v4.0+
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181518490.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 460c35b2b54d9ac032c331cab18583f39d54bac7..2d83f1dfb4d69a08a9fbcffa2088726f9507ecbf 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3150,7 +3150,7 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 
        serial8250_set_divisor(port, baud, quot, frac);
        serial_port_out(port, UART_LCR, up->lcr);
-       serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
+       serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS);
 }
 
 /*