From: Maciej W. Rozycki macro@orcam.me.uk
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.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_port.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -3311,7 +3311,7 @@ static void serial8250_console_restore(s
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); }
/*