Intel Quark has 16550A compatible UART with autoflow feature enabled. It has
only 16 bytes of FIFO. Currently serial8250_do_set_termios() prevents to enable
autoflow since the minimum requirement of 32 bytes of FIFO size.
Decrease a FIFO size limitation to 16 bytes to allow autoflow control be
enabled on such UARTs.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e213da0..3f8121e 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2522,9 +2522,9 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
* the trigger, or the MCR RTS bit is cleared. In the case where
* the remote UART is not using CTS auto flow control, we must
* have sufficient FIFO entries for the latency of the remote
- * UART to respond. IOW, at least 32 bytes of FIFO.
+ * UART to respond. IOW, at least 16 bytes of FIFO.
*/
- if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) {
+ if (up->capabilities & UART_CAP_AFE && port->fifosize >= 16) {
up->mcr &= ~UART_MCR_AFE;
if (termios->c_cflag & CRTSCTS)
up->mcr |= UART_MCR_AFE;
--
2.8.0.rc3
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
