Messages in this thread Patch in this message | | | From | Andy Shevchenko <> | Subject | [PATCH v1 08/12] serial: 8250: enable AFE on ports where FIFO is 16 bytes | Date | Thu, 7 Apr 2016 23:37:09 +0300 |
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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@linux.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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