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Message-Id: <1460061433-63750-9-git-send-email-andriy.shevchenko@linux.intel.com>
Date: Thu, 7 Apr 2016 23:37:09 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Vinod Koul <vinod.koul@...el.com>, linux-kernel@...r.kernel.org,
dmaengine@...r.kernel.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
ismo.puustinen@...el.com,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
linux-serial@...r.kernel.org
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1 08/12] serial: 8250: enable AFE on ports where FIFO is 16 bytes
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@...ux.intel.com>
---
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
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