[PATCH 09/24] USB: serial: opticon: fix TIOCGSERIAL implementation

From: Johan Hovold
Date: Wed Apr 07 2021 - 06:40:29 EST


TIOCSSERIAL is a horrid, underspecified, legacy interface which for most
serial devices is only useful for setting the close_delay and
closing_wait parameters.

The xmit_fifo_size parameter could be used to set the hardware transmit
fifo size of a legacy UART when it could not be detected, but the
interface is limited to eight bits and should be left unset when not
used.

Similarly, baud_base could be used to set the UART base clock when it
could not be detected but might as well be left unset when it is not
known.

The close_delay and closing_wait parameters returned by TIOCGSERIAL are
specified in centiseconds (not jiffies). The driver does not yet support
changing these, but let's report back the default values actually used
(0.5 and 30 seconds, respectively).

Fixes: faac64ad9c7b ("USB: serial: opticon: add serial line ioctls")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/opticon.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index eecb72aef83e..1c7e5dc2c272 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -360,12 +360,9 @@ static int get_serial_info(struct tty_struct *tty,
/* fake emulate a 16550 uart to make userspace code happy */
ss->type = PORT_16550A;
ss->line = port->minor;
- ss->port = 0;
- ss->irq = 0;
- ss->xmit_fifo_size = 1024;
- ss->baud_base = 9600;
- ss->close_delay = 5*HZ;
- ss->closing_wait = 30*HZ;
+ ss->close_delay = 50;
+ ss->closing_wait = 3000;
+
return 0;
}

--
2.26.3