diff mbox series

[v4,4/5] serial: 8250: Also set sticky MCR bits in console restoration

Message ID alpine.DEB.2.21.2204162156340.9383@angie.orcam.me.uk
State New
Headers show
Series None | expand

Commit Message

Maciej W. Rozycki April 17, 2022, 11:02 p.m. UTC 
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+
---
New change in v4, factored out from 5/5.
---
 drivers/tty/serial/8250/8250_port.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

linux-serial-8250-mcr-restore.diff
diff mbox series

Patch

Index: linux-macro/drivers/tty/serial/8250/8250_port.c
===================================================================
--- linux-macro.orig/drivers/tty/serial/8250/8250_port.c
+++ linux-macro/drivers/tty/serial/8250/8250_port.c
@@ -3308,7 +3308,7 @@  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);
 }
 
 /*