| Message ID | 20231226121607.GA2622970@ravnborg.org |
|---|---|
| State | New |
| Headers | show |
| Series | serial: apbuart: fix console prompt on qemu | expand |
diff --git a/drivers/tty/serial/apbuart.c b/drivers/tty/serial/apbuart.c index 716cb014c028..364599f256db 100644 --- a/drivers/tty/serial/apbuart.c +++ b/drivers/tty/serial/apbuart.c @@ -122,7 +122,7 @@ static void apbuart_tx_chars(struct uart_port *port) { u8 ch; - uart_port_tx_limited(port, ch, port->fifosize >> 1, + uart_port_tx_limited(port, ch, port->fifosize, true, UART_PUT_CHAR(port, ch), ({}));
When using a leon kernel with qemu there where no console prompt. The root cause is the handling of the fifo size in the tx part of the apbuart driver. The qemu uart driver only have a very rudimentary status handling and do not report the number of chars queued in the tx fifo in the status register. So the driver ends up with a fifo size of 1. In the tx path the fifo size is divided by 2 - resulting in a fifo size of zero. The original implementation would always try to send one char, but after the introduction of uart_port_tx_limited() the fifo size is respected even for the first char. There seems to be no good reason to divide the fifo size with two - so remove this. It looks like something copied from the original amba driver. With qemu we now have a minimum fifo size of one char, so we show the prompt. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Fixes: d11cc8c3c4b6 ("tty: serial: use uart_port_tx_limited()") Cc: Andreas Larsson <andreas@gaisler.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: linux-serial@vger.kernel.org Cc: sparclinux@vger.kernel.org --- drivers/tty/serial/apbuart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)