On 05/26/2015 10:26 AM, Duan Andy wrote:
> From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> Sent: Tuesday, May 26, 2015 9:27 PM
>> To: Duan Fugang-B38611; gregkh@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-serial@xxxxxxxxxxxxxxx
>> Subject: Re: [PATCH] serial: core: don't set console cflag to zero
>>
>> On 05/04/2015 03:56 AM, Fugang Duan wrote:
>>> From: "Fugang Duan" <B38611@xxxxxxxxxxxxx>
>>>
>>> In android without shell environment (androidboot.selinux enable), do
>>> suspend/resume test, console terminal has no message print out. The
>>> issue is reproduced at i.MX serial platforms like i.MX6Q/DL/SX.
>>>
>>> In common code, cons->cflag is cleared to zero in
>>> .uart_port_startup(), but after resume back, use the cons->cflag to set
>> termios.
>>> ......................
>>> uart_port_startup->
>>> uport->cons->cflag = 0;
>>>
>>> uart_resume_port()->
>>> termios.c_cflga = uport->cons->cflag;
>>> ...
>>> uport->ops->set_termios(uport, &termios, NULL);
>>> ......................
>>>
>>> If the console baud rate is 115200 bps, after Android resume back, the
>>> console baud rate is initialized to 9600 bps. So the patch save the
>> console cflag.
>>>
>>> Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx>
>>> ---
>>> drivers/tty/serial/serial_core.c | 5 ++---
>>> 1 files changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/serial_core.c
>>> b/drivers/tty/serial/serial_core.c
>>> index 0b7bb12..4b21091 100644
>>> --- a/drivers/tty/serial/serial_core.c
>>> +++ b/drivers/tty/serial/serial_core.c
>>> @@ -162,10 +162,9 @@ static int uart_port_startup(struct tty_struct
>>> *tty, struct uart_state *state,
>>>
>>> retval = uport->ops->startup(uport);
>>> if (retval == 0) {
>>> - if (uart_console(uport) && uport->cons->cflag) {
>>> + if (uart_console(uport) && uport->cons->cflag)
>>> tty->termios.c_cflag = uport->cons->cflag;
>>> - uport->cons->cflag = 0;
>>
>> NAK. Please fix your userspace, which is opening the serial port used by
>> the console with incompatible line settings.
>>
>> Regards,
>> Peter Hurley
>
> In Android with shell environment, and there have no app to open the serial port, how to fix it in userspace ?
The only way that uart_port_startup() is called is if userspace opens
the serial port.
Regards,
Peter Hurley
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