Alan Cox wrote:
>> It looked like the API for the tty subsystem was gradually changing such
>> that the ldisc structure could ultimately get shared for use with the
>> console, but this work is not complete, so we are somewhere in between.
>
> The mechanics of this are already there. A tty drive can manage its own
> termios structs, and the termios structs are pointers in the tty structure
>
>> The question is what is an acceptable solution?
>
> Take a look at usb_serial.c:serial_install. You can do the console state
> preservation there and cleanly.
>
Thanks for the pointer Alan. That solves the termios initialization
piece nicely.
In the usb git tree the serial_install() got removed, but I can see
the init_termios structure that gets setup in usb_serial_init().
The patch will look something like the code below, but we have to sort
out the patch tree with Alan Stern's changes to usb/serial/console.c.
Thanks,
Jason.
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
drivers/usb/serial/console.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -65,7 +65,7 @@ static int usb_console_setup(struct cons
struct usb_serial_port *port;
int retval = 0;
struct tty_struct *tty = NULL;
- struct ktermios *termios = NULL, dummy;
+ struct ktermios dummy;
dbg("%s", __func__);
@@ -136,14 +136,7 @@ static int usb_console_setup(struct cons
goto reset_open_count;
}
kref_init(&tty->kref);
- termios = kzalloc(sizeof(*termios), GFP_KERNEL);
- if (!termios) {
- retval = -ENOMEM;
- err("no more memory");
- goto free_tty;
- }
- memset(&dummy, 0, sizeof(struct ktermios));
- tty->termios = termios;
+ tty->termios = &usb_serial_tty_driver->init_termios;
tty_port_tty_set(&port->port, tty);
}
@@ -156,16 +149,15 @@ static int usb_console_setup(struct cons
if (retval) {
err("could not open USB console port");
- goto free_termios;
+ goto clear_port_tty_set;
}
if (serial->type->set_termios) {
- termios->c_cflag = cflag;
- tty_termios_encode_baud_rate(termios, baud, baud);
+ tty->termios->c_cflag = cflag;
+ tty_termios_encode_baud_rate(tty->termios, baud, baud);
serial->type->set_termios(tty, port, &dummy);
tty_port_tty_set(&port->port, NULL);
- kfree(termios);
kfree(tty);
}
}
@@ -180,13 +172,11 @@ static int usb_console_setup(struct cons
out:
return retval;
-free_termios:
- kfree(termios);
+clear_port_tty_set:
tty_port_tty_set(&port->port, NULL);
-free_tty:
kfree(tty);
reset_open_count:
- port->port.count = 0;
+ --port->port.count;
goto out;
}
--
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