Hi Greg,
On 02/07/2016 07:19 AM, Greg KH wrote:
> On Tue, Dec 08, 2015 at 12:15:00AM +0100, Hauke Mehrtens wrote:
>> The Arduino Yun uses a baud rate of 250000 by default. The serial is
>> going over the Atmel ATmega and is used to connect to this chip.
>> Without this patch Linux wants to switch the console to 230400 Baud.
>
> Even if you ask for it to be the other rate?
Asking for something else does not work. The serial is connected to a
ATmega32U4 and by default a program which is statically configured to a
baud rate of 250000 is running there. It should work when I replace this
program with something else.
Am I the first one who needed a strange baud rate for the boot console?
>> With this patch Linux will use the configured baud rate and not some
>> standard one which is near by.
>
> Hm, I'm worried about this change, have you tested it on a "normal"
> system?
I have tested it on some "normal" system I think. I am also unsure about
this patch and want to get some input from the serial driver experts here.
>>
>> Signed-off-by: Hauke Mehrtens <hauke@xxxxxxxxxx>
>> ---
>> drivers/tty/serial/serial_core.c | 13 ++++++++++---
>> include/linux/console.h | 1 +
>> 2 files changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
>> index def5199..fcdf258 100644
>> --- a/drivers/tty/serial/serial_core.c
>> +++ b/drivers/tty/serial/serial_core.c
>> @@ -164,6 +164,8 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
>> if (retval == 0) {
>> if (uart_console(uport) && uport->cons->cflag) {
>> tty->termios.c_cflag = uport->cons->cflag;
>> + tty->termios.c_ospeed = uport->cons->baud;
>> + tty->termios.c_ispeed = uport->cons->baud;
>> uport->cons->cflag = 0;
>> }
>> /*
>> @@ -1909,7 +1911,7 @@ static const struct baud_rates baud_rates[] = {
>> { 4800, B4800 },
>> { 2400, B2400 },
>> { 1200, B1200 },
>> - { 0, B38400 }
>> + { 0, BOTHER }
>> };
>>
>> /**
>> @@ -1948,10 +1950,13 @@ uart_set_options(struct uart_port *port, struct console *co,
>> * Construct a cflag setting.
>> */
>> for (i = 0; baud_rates[i].rate; i++)
>> - if (baud_rates[i].rate <= baud)
>> + if (baud_rates[i].rate == baud)
>> break;
>>
>> termios.c_cflag |= baud_rates[i].cflag;
>> + if (!baud_rates[i].rate) {
>> + termios.c_ospeed = baud;
>> + }
>
> Minor nit, coding style :(
Sorry, will fix this.
> Always run your patches through scripts/checkpatch.pl please.
Hauke
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